I'd bet there is something on the floor that impregnated into the grout, wax, mop and glow, etc. Acid won't help much. Strippers Barebones,Johnson Fastrip etc and even then you have to set expectations that it's going to be spotty.
I run in to this all the time at commercial accounts that have a maint crew that does VCT they wax everything.
I run in to this all the time at commercial accounts that have a maint crew that does VCT they wax everything.
