Tips---Nail Polish

Hello, I was having my yearly mammogram this morning and found these tips in one of their office magazines.
#1. Secure a screw by brushing some clear nail polish on the screw threads. In sert the screw and let dry before using it again. They say it also helps to keep the screw from rusting.
#2. Stop tarnish of costume jewelry from turning black with a coat of clear polish.
#3. Seal an envelope by brushing the underside of the flap.
#4. Mend a screen hole no bigger than 1/3 inch by brushing a little clear nail polish over the spot.
I need to try the jewelry and the envelope tip. I always have a problem with the envelopes sealing. I think they use less glue or I must buy cheap envelopes.
Please have a mammogram every year. Both of my sister's had breast cancer and survived. My aunt and her daughter did not. Take care of yourself!