Need a red switch and don't have one in stock? Red finger polish will work and last forever.
It works well on your TV tuner too to hi lite those buttons you never can find. It will chip off after a couple months so just re-paint them.
I use it on special plugs, marking where off is on the hard to see dial on the gas grill, any number of places. Holds up well and most houses have it. I keep a bottle in the tool crib.