Can we have a "lock" feature for spare covers?

Can we get a lock feature for spare covers please? If I’m saving a cover whilst I build ISO to chap a character, I have to sell covers individually to avoid selling the cover I’m keeping. Putting a lock on this character to prevent it being sold accidentally would mean I could “sell all” without worrying & take less time.

Apologies if it’s already been suggested, but I couldn’t see anything.

What would incentivize you to buy HP or ISO then?

I think the OP means that there would still be an expiration timer. He just wants to be able to protect covers from being automatically sold via the “sell all” button.

Spot on.