I want to clean some rust stains off the GRP this weekend.. It's too late to order oxalic acid online and be sure to get it by Friday afternoon so I need to get something from the high street..
The usual selection of shops around eg. Sainsburys, Tesco, Wickes, Halfords etc..
I have looked at the Harpic toilet cleaner with lime scale remover and it contains Hydrochloric acid.. Other cleaners in the house I have looked at have citric acid but nothing so far with oxalic acid..
Which household products available in these stores would have a high enough concentration of oxalic acid to do the job??