We’ve been mucking around in the lab with a phosphoric acid based rust remover for the past couple of weeks and we’ve been getting good results.
Whilst it is based on phosphoric acid we’ve added a few select surfactants in to help it lift dirt and grime as well as helping it remove rust. It will also work to remove cement from tools, flooring etc, which is useful in the building trade.
Below are some pictures of what it can do diluted down 5:1 in an ultrasonic bath.