Sorry Chas, I don't agree...once they are washed, if they shrink they will be useless as patterns to make new...
I think I would try dyeing them first, you aren't going to lose anything, especially if you end up making or buying new ones.
IF you do decide to wash/dye them...take LOTS of measurements first!!! And let them drip dry...no dryer, the heat will make them shrink even more.
Learn from my mistake ~
I thought I could wash the upholstery covers for our cushions because they were made of "synthetic polyester so they should have been unshrinkable"....NOPE, I was wrong! They shrank up something awful and the unseen (before washing) worn portions became threadbare & shreaded! Unfortunately, I didn't take measurements and had to start from scratch for the new ones.
Here's a link
to our webpage for additional cushion information....
Fortunately, I'm a pretty quick study & learned from my upholstery experience before washing the drapes (duh). I used the old drapes as "go by" patterns to make the new drapes
. I realize the drape style in your '85 is different than our '64, but I would give it a shot...or order them from Jim Abruso.