Kehfee
Verified Trader
And if you do break them, make sure you keep the label so at least if someone buys it from you, they can have it resealed at ITG.
While I agree with keeping the label. I don't think ITG is going to reseal a card that has been completely broken out. They'd have no way of verifying the memorabilia hasn't been tampered with.
Damaged holders I can see. If the seal is still intact. They may also reslab base and non-GU cards as they wouldn't have been tampered with.