Last week I made a post about removing kitchen vinyl floor tiles. I've
managed to get them off and have seen replies about using a hot air gun and
scraper to remove them. I managed to do it with a hammer and thin wall
scraper.

I am now left with a floor which you can see patches of concrete but most
of it is black. I'm getting as much adhesive off as possible but the black
stuff is pretty impossible to remove and feels like a rubber texture. I'm
sure that this is probably because of the adhesive but does it matter if it
stays like that if i'm placing ceramic tiles over it? Would the norm of
sealing it with PVA have an issue of the new adhesive bonding to the floor?

TIA