Dude… cutoff discs are like less than $1 each at harbor freight, I just toss them when they start wearing. Too paranoid about it starting to throw chunks as it deteriorates or develop uneven wear or a dozen other things I don’t want to have to worry about with something that’s cheaper than tissue paper.

Here’s a link to a 10 pack for $5.99, use the coupon code and it’s even cheaper.

https://www.harborfreight.com/power-tools/grinding-cutting-wheels/cut-off-wheels/3-in-x-116-in-x-38-in-metal-cut-off-wheels-10-pack-61354.html

They’re consumable, just toss them once they wear out