My elderly (87 y.o.) dad wants to coat his garage floor before selling his house. I power washed the floor, then washed it with a concrete cleaner. There are still a few spots that turn water though. Will the cleaner /etcher take care of this so the epoxy sticks to the floor, or do you have to grind away the surface of the concrete so the epoxy will stick ? Any advice is welcome. House is about 30 years old . Floor looks new btw. Would muriatic acid be helpful? Thanks in advance for any advice.

