FWIW, I paint my prop tips either yellow or white. I use Testors enamel.

After painting both tips, I'll balance the prop. Sometimes, the difference in balance is so little that I can just add paint to the light tip.

Good advice about not to reaching over the prop, fastplane. Red Baron 77 and CCRC1 have good advice too.

The painted prop tips are a nice reminder of where they are....

Bob