Thanks for the replies!
Melting it into the bucket is a good idea, I'll have to check with a family member to see if they have some kind of tool that would work to do it. I'd also thought of engraving them, but wasn't sure how well that would work either or if it would just end up looking like scratches.
I was thinking about spray painting something on there, but I wasn't sure how it would hold up to scrubbing.
And Delfina, I'm pretty sure there's every color under the sun in this barn. I know for a fact there's neon pink, lime green, and orange. And I want there to be a definite way to prove they're mine.