Kactapuss

Do the opposite, rust the whole sign and then grind the raised letters back shiny?

Agreed that saftey is important, I still have all my fingers and intend to keepnit that way... But Instructables is not safety school. It is your responsibility to supervise your children on the internet, regulate their access to power tools, and teach them enough common sense to know not to try advanced techniques with potentially dangerous shop tools it they don't have experience.