Funny, my mom has a bunny tattoo just like that, and an ankle tattoo just like that too.... Hey, wait a minute...
Probably to clean grease off the floor with. Most shops I know just wash down the floor, spread some powder laundry soap on it, and then get busy scrubbing with a garage broom, rinse, and repeat.
Aluminum does not rust! Aren't Ferrari engines aluminum? They have sleeves that could probably rust but the aluminum cannot! What say you.