H2O2 in H20, Stability

It'll last that long. Don't cap it tightly. As the peroxide works on the stuff on the screen and the screen itself, the concentration will go down. You should see bubbles on the screen throughout the process.

http://www.bold-tech.com/technical/piranha_etch.html" [Broken] It works!

 

My previous company produced it in batch quantities at 1% and stored it for a 4 days at the most at room temperature. It isn't that interesting at low concentrations however there are all sorts of problems with it at high concentrations - be certain to not get it on flammable surfaces e.g. wood and even leather shoes if you are wearing one even a few drips may cause it to catch fire.