Paper napkin. I've done it before.
I keep a Singer key on my key ring. GF has 3 or 4 styles on hers. Opened this one with an awl blade on my Swiss Army knife.
KarenH It was serviced at Will Rogers Sewing Machine shop Lee East may be the proprietor.
Base has been modified, but it works well.
Have you been to the museum at 55th and Peoria?