For cleaning concrete block, we've been using pool chlorine for years. Buy it by the gallon at Home Depot. Spray it on, let sit for a few minutes and hose it off with high pressure. DO NOT spray on signs or get it on your clothing as it makes a stain that will be there forever. It works especially well on green moss and that black stuff that grows in the crevases of the block. Hope this helps. DendukeWhat is the best chemical to clean block walls in my SS bays. Will it harm the bay signs or stainless?
Thanks,
Kirb
Have you ever put muriatic acid in one?Waxman said:I disagree about the necessity of acid-proof, pump-up sprayers.
The best I have used are the cheapest from ACE Hardware. Around $20 and has lasted me a year.