Answer:
No matter how little or how much you use me, you change me every month.
Whiling away the hours of flowers, Walking through fields of gold. Preening and pruning in lights fading hours, For petals to freeze in the cold. What is it?
Three lives have I. Gentle enough to soothe the skin. Light enough to caress the sky. Hard enough to crack rocks.
You use it between your head and your toes, the more it works the thinner it grows.
Although I'm not an insect, some people found me very difficult to exterminate. They called me something like 'insane priest.' The first half of my name means the same as 'scrape,' & my last three letters are a metal. Who am I?