Vintage clothing, of course, shouldn't be treated like regular new clothing. Even though the pieces were strong enough to last 50 or more year, they still need special treatment when cleaning or storing. The tips here are how I handle my own vintage clothing that I sell and that I collect and wear myself. Everyone who sells or collects or wears vintage clothing has their own way of handling vintage, so this is not the be-all and end-all of care instructions. It works for me. Each week, I'll focus on a different type of care, cleaning, repairing, storing etc. I may go back to previous tip posts to revise or add info that I've forgotten.
Cleaning - You need a basic knowledge of some fabrics to know how to clean vintage clothing. Cottons, nylons and polyesters are usually pretty safe to handwash. I rarely put vintage in the washing machine, because you never know how a garment will come out. Some pieces may look and feel perfectly strong and durable, but get them wet, and they may fall apart, even if you handwash them. It's just something that you cannot predict, even after handling vintage for years now, I still get a piece that will unexpectantly fall apart when I wash it.
If it's just a light cleaning that you need, some cool water in the sink or tub with some Ivory soap is fine. Rinse it well and either lay flat or hang to dry. I had a 2nd shower rod down the center of my tub for hanging vintage to dry. Each morning I usually had to move clothes just to get into the shower to clean myself! Sturdy cotton, nylon & poly pieces will be safe in a dryer on low tumble.
Now, if you have stains that won't come out in a light soak, then I suggest Biz which is safe on nylon, polys and cottons. The exception would be for cottons that have heavy or intricate dye designs, or metallic dye, any of which may fade in Biz or in just about any soak anyway. But your basic cotton prints will be fine. Biz is a powder and it can be bought at Kmart, Target or Walmart. I usually melt some Biz in a little very hot water, and then lower the temp to a warm water that I can put my hands in. Fill the tub for several like-color items or wash a single item in the sink. Sometimes the dirt comes out immediately, and you'd be amazed at how much dirt comes out of some items. I've had great success soaking nylon tulle prom gowns in the tub and those always seem to hold a ton of dirt. Again, you may see immediate results and be able to rinse out the item in a short time. But other items may have more stubborn stains and require longer soaking. I've soaked some things in Biz for several days, adding more Biz and more hot water. If it is a pure white item that you are having trouble returning to pure white status, you might add a teeny bit of bleach in the water and Biz. This usually does the trick for stubborn browning or yellowing. That's for all-white items only now, no prints or other colors in the white. Biz is great for white linens and for Victorian or Edwardian white clothin. I don't recommend adding any bleach with those though very old items, because the fabrics may be too delicate for that. Wetting linens in Biz and water and then hanging them out in the sun does good for whitening too. Again, after a Biz soak and very good rinsing, hang dry or lay flat to dry. Tumble dry on low for lightweight things like nylon.
If you have a specific stain that you want to get out of any cotton or nylon item, fold the item with the stain laying on the top and set the item in a sink or pot. Put hot water in the sink, just enough to wet the item and leave the stain floating on the top of the water. Then poar dry Biz directly onto the stain in a little pile, and leave it to soak. The dry Biz will soak up a little of the water and make it's own paste on top of the stain. This usually works to draw out the stain within a few hours, then just rinse and dry.
Don't spend too much time on a single stain, sometimes they just won't come out. Even if you make it fade a little, you should feel some sort of satisfaction. Remember, that stain may be 50 years old, it's gonna be hard to get rid of it now, especially if the previous wearer was unable to get it out 50 years ago. Some stains just won't budge or come out completely. I'm not a fan of Oxyclean. It does work on most stains, but never use it on silk or rayons, or bright prints. I just prefer Biz.
Underarm stains - If it is an old stain, most likely it is not going to come out. Certain fabrics are permanently discolored by perspiration and will just be impossible to clean. Cotton, nylon and poly soaked in Biz usually clean up fairly well. Dry Biz (as described in the folded soaking method above) directly on the under arms may clear up more stubborn stains. Rayons and silks are the type of fabrics that turn and fade from perspiration so they don't usually clear up as well. Using deluted white vineger on a washcloth and dabbing the under arm may help a little. If the rayon or silk is colorfast you may be able wet the under arms a little more, but be careful! Dry cleaning may help, but like I said, if it's very old, or if it has actually changed the fabric, it won't be much help.
Cleaning Rayons & silks - Most are handwashable if you are careful. The exception is creped rayon/acetate. Most cocktail dresses are made of this fabric, tons of little black dresses are made of this fabric. In the 1930-40s the weave was a little looser, more textured. By the 1950-60s, it was a tighter neater weave. Most of these later pieces are lined in acetate taffeta. The problem with these crepes is they pucker like crazy when they get wet. Most will shrink several sizes and loose their shape. I've heard people claim to have washed and re-shaped crepe dresses, either they weren't really rayon/acetate crepe or else the people were exagerating. It would take a great deal of patience to reshape, plus the crepe tears easy when wet. They'll never be the same size again, and if they have an acetate lining, the crepe will pucker up all along the seams where it is attached to the crepe. The crepe will also end up several sizes smaller than the lining. Creped rayon/acetate is definately a dry clean only fabric. To test if your item is this mad-shrinking fabric, wet a little spot inside of the hem or inside of the lining, just a tiny wet spot will pucker immediately if it is crepe.
But light colored solid silks and silky-like woven rayon (like lingerie rayon) can be soaked with care. I would not wet silks that are dyed dark colors or that have printed designs. Those colors are going to run when you wet it. Some people say that you can soak a silk item in vinegar to set the color and then wash it. But I have never tried that. For light washing, you can use a little Woolite in cool water for washable silks and rayons. Something else that I've used on delicates is Eucalan - http://www.eucalan.com/ - which is really made for sweaters, but is also recommended for delicates. It has fabric conditioners and it is no rinse. Good for light cleaning, but it does not work on stains. For items with stains, you can soak washable silks and rayons in Biz too, but after melting the Biz in hot water, add cool water before you add the item. Test for colorfastness or watch it closely as you put it in the water. You may see a little bit of color come out. If the color in the water is different from the color of the garment, it is just dye residue and it should be fine to continue soaking, you may have to change the water after a few minutes. But if the water turns the color of the item, then it is the dye itself coming out, so get it out of the water right away, that means it is NOT colorfast and will fade in color. I don't soak silks in Biz very often, because it can be harsh on such a delicate fabric. I usually only try it if the item is a 'lost cause' to begin with, something that I would probably sell as-is because of stains. But I've been surprised how some silks clean up. I've also been surprised by some silks falling apart in the water. That's not the Biz fault though, that would have happened with any cleaner or even in just plain water. Some fabrics are just rotten, even if they don't appear damaged.
I've also used my Biz paste soak on stains on washable rayon and silk items, including a 1930s silk satin Harlow gown, with nice results.
Dry cleaning - The only thing that I can recommend is checking the cleaners in your area by asking them if they handle vintage items. You might want to remove any special buttons from your vintage items before leaving them at the cleaners. Ask how they handle items with sequins and rhinestones. Ask what their policy is if they damage your item. I would limit the number of times that you dry clean vintage. The chemicals can be harsh on some older fabrics, so do it sparingly.
Buying vintage with stains - don't buy anything stained unless you are pretty sure that you can get out the stains, or unless it is super cheap. In the beginning of my stock buying, I bought tons of stuff with stains, thinking that I'd find a way to clean them. Now for me, I just don't have the time to spend hours on a single garment anymore, so I usually pass up things that look like a big project. But you may have some fun with a project like that, and it is very satisfying to make a lost cause a fabulous addition to your wardrobe. Take a before photo so that you can share your glee and pride over your cleaning skills to anyone who compliments you when wearing your magically cleaned item. If you are buying from a dealer, a vintage shop or even a thrift shop, and you point out the stain to the seller, don't believe the seller if they say 'oh that stain will wash out very easy' - if it's so easy to wash, they should have washed it themselves. Otherwise they should be selling it for a discounted price, not full retail. Don't pay for stains. I clean everything to the best of my ability, and I discount my items according to any stains that I couldn't get out, and I point them out in my discriptions. I don't try to pass anything by my buyers, but I've come across dealers who either don't look over the items closely enough before they price them, or else they are trying to pass damage/stains by the buyers. The only thing that I wouldn't wash is something that is already unwearable. On Victorian and Edwardian white items, sometimes I wash them, and sometimes I sell them as found, which I mention in the description. With those items, some people want them nice and white to possibly wear, and some people like them with the natural aging. So I sell them both ways.
Wow, this is turning out to be a very big essay! There's probably alot more that I could add, but this is what I have for now.