I had some Cabot Wood (deck) cleaner spill on my garden tools (in particular a couple of shears). It probably sat there for a few weeks before I noticed it. Now the steel parts are quite corroded. What’s a good way to clean them up? Are there particular household chemicals / cleaners that would be good for this?
My goal is to prevent further damage and restore them to looking less-bad.
There is not likely much metal loss from steel . Simple wire brushing should clean them . To go a step further; treating them with a "conversion " coating and oil would slow future rust. Conversion coating will contain phosphoric acid ; one brand is Navel Jelly. They convert oxides, etc, to more stable phosphates. Cutting edges could benefit from sharpening.
If you go to the Cabot web site and look for the CPIC information it informs that the cleaner consists of water plus sodium and calcium salts that perform various functions, one of which is to make the tool surfaces more electrochemically reactive. So the effect will be much like road salt on vehicles, some corrosion. A common method for handling the situation is to dry off and clean the tools as soon as possible to stop the corrosion, and then use elbow grease with steel wool dipped in a little household oil. There may be some pitting visible, but since these are holes in the metal not much to be done there except reduce to bare metal where possible without affecting the inherent strength of the structure.
