I found these Valentines (and others) in an old scrapbook dated 1949.
The pages in the scrapbook were crumbling so I took the pages out and used vinegar to soak the glue loose. I'd never tried that before and I was afraid it would ruin them.
The paper peeled easily off the backs. I dipped them in a baking powder solution to neutralize the vinegar and laid them on a smooth hard surface to dry.
Much to my surprise them came out looking great, clean and bright, and no damage.
I found the scrapbook in a wonderful old junk store on the way to Selma last Fall, in the tiny town of Maplesville. Of course I forgot to take any pictures of said store and it was worthy of a blogpost all it's own. The proprietor's name was Rembrant. I don't think the store had a name but it was in a 19th century store building unchanged since the day it was built.
I did get a picture of the sunset on the way home that day.