: I have found that Borax acid works best when you use a disposable container
: (coffee can), with boiling hot water in it. Add Borax crystals until you
: have a supersaturated solution (when no more borax will dissolve) . . .

OK, there seems to be some confusion about the materials involved. Borax is an alkaline compound, sodium borate. Boric acid is an acid.

Borax is used in the home as a washing additive to soften water and emulsify dirt. It is what I suggest as a compound for washing away mildew. A common brand is "20 Mule Team" borax.

"Boraxo" is a tradename for a washing material which has borax in it, but I'm not sure what else is in it. You might try it if you want to experiment.

Boric acid is used in the home as an antiseptic, in weak solutions as an eye wash, or in greater concentrations as a bug killer. (Roach Prufe is something like 98% boric acid) This is not the material I suggested.

All these materials are derived chemically from the element Boron, and that is where the similarity ends. they are wuite different materials. Confusing boric acid for borax is like confusing table salt (sodium chloride) with laundry bleach (sodium hypochlorite). Ain't chemistry grand!

hope this helps

PGJ