Taking good care of your vintage clothes is much easier than you'd expect.
This is a quick how-to guide for keeping your finds in good shape.
The most important thing to know is if the item can be washed in a machine or not. Typically anything made of wool or rayon is a no-no. Those should be dry cleaned only. Wool will lose its shape and often develop holes, and rayon will shrink and wrinkle beyond repair. Just don't do it! I've ruined a perfectly good rayon dress by washing it in a machine and have seen gorgeous vintage wool cardigans resemble Swiss cheese after a washing machine session.
Polyester and cotton are generally safe to machine wash. That said, always use the delicate cycle with cool or cold water. Use gentle detergent. Using the dryer is usually fine, but again - think gentle. Low heat! You can also air dry and then hit it with an iron later to tackle any wrinkles.
Don't wash in a machine: fancy dresses, anything with delicate embellishments, anything super old (older than the 1960's is my personal cut off!), coats of any kind, wool blend sweaters.
Usually fine in a machine: 60's and 70's polyester stuff washes and dries awesome. Newer cotton items (70's and later) are fine too.
Solutions for items that can't go in the machine: Soaking. Yep, soaking in a (clean!) bathtub with tepid water and Woolite. This will at least clean up the garment. It probably won't lift stains or anything like that. Gently squeeze out excess water after rinsing and dry flat. Extra bonus for drying it outside on a warm spring or summer day. Again, do not put rayon or wool or anything super old or elaborate in the bathtub. Save those for a professional dry cleaner.
One final word: do you have leather, suede, or fur that needs to be cleaned? Take those to a professional "furrier". Skip dry cleaning on those.