I have some old lace that my grandmother made and was stored in my mom's basement. They were a kind of grey color. I used retro clean and I was amazed at the difference in the color. They also had some rust on them--gone after a good soak. I think you should try to remove the stains before storing them again. The fabric might disintegrate if you don't. One day you might get a wonderful idea and want to use them.
Sue