deposit deduction for stained kitchen countertop

[Steve C.]

Kitchen countertop got stains during current tenant's residency.

It doesn't have any functional issue,
but it does look really ugly.

I tried multiple chemicals including Comet to remove it, but didn't worked.
My contractor told me that it seems that something has peeled off from this laminate material.
It is obviously damaged, but which amount would be fair to charge against the tenant.
I don't think it's fair to charge the amount for replacing the whole countertop which might cost like $1500. But at the same time, I can't charge any cleaning fee since it can't be cleaned at all.

Any suggestion or advice?