HiMedia GRM1108-100G 1H-Benzotriazole, Extra Pure, 100 g

I made a 1% solution by weight, dissolved in propylene glycol for use as an anti-fog agent when developing expired black and white photography film. Benzotriazole is fairly insoluble in water, but dissolved readily at room temperature in propylene glycol. 12-15 drops in a 20 ounce developing tank restrains the developer in a way that reduces age-related chemical and background radiation base fog without materially affecting normal development. Your mileage may vary, but works many times.

I mixed 1 gram of this into a half gallon of water (also added about a cup isopropyl alcohol to help it dissolve). I soaked my clean brass casings in the solution for about 10 minutes. So far they have not tarnished or changed color. I've been reloading 308 and 223 rounds for about six months and this is the best method I found so far for preserving the brass.

It's exactly what's on the label. Good purity too.

Look at the active ingredients in certain commercial coolants. Benzotriazole is in some of them. Benzotriazole specifically is a copper passivating agent, creating a complex with the surface of the copper preventing corrosive effects. This won't help you nickle plated dudes, which yeah is the majority at this point I think. However, for those of us who still run 'absolutely no nickle' builds like myself, this will keep your build looking pristine inside.You need heat to dissolve this into solution, and I have noticed a bit can fall out of solution as a kind of white ooze. It'll redissolve and because I know what it is I have no problem with it (unlike a certain commercial Slovenian coolant.).