phosphoric acid can be used fairly straight w/o damage, but can also be diluted w/ water - the more water the slower the action, and it can be used over and over til it collects too much junque

Bill

Moved over to the Passing Lane

"When we tug a single thing in nature we find it attached to the rest of the world" John Muir
"When we tug a single thing on an old truck, we find it falls off" me
Some TF series details & TF heater pics & Rust-a-holics Unanimous parking lot