One of my bettas, Finley, is a chronic tail-biter

I try to make his tank really fun for him so that he'll be too busy to even think about taking a chomp out of his tail. it seems to be working pretty well, he's letting his rays grow out a little now (he's a crown tail). Anyways, there's an antique store in my town that has TONS of paper weights like this one:

if i get one of these, and rinse it really well in scalding hot water, will it be safe to use it in his tank?? I think it would be really cool, and it would be something new and interesting for him to explore!
Also, here's a picture of his current set-up. if anyone else has any decor ideas, or tips to cut down on his tail biting, i'd really appreciate it =)
And here's a picture of Finley, just for fun

i think he's quite handsome with or without his rays, but it would be nice if he would let them grow back in completely

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