A friend has a Jacuzzi tub with plastic insert "walls". The was mildew
on the grout which she attempted to hide with some sort of quick-fix
grout. The mildew now looks terrible and I want to get rid of it all
and redo it. What can I use to clean it out but not hurt the tub? A
sharp chisel might work. Are there solvents or cleaning chemicals?
Dremel tool? Wire brush???