I use a combo of WD-40 and a green scotch brite pad on my ROS to remove rust and any waxy build up.
- Tony1212
Since paste wax is; wax dissolved in petroleum solvents, unless rust has been there for long time and started to create pitting; the extra step of using WD40 is simply adding more work. IMHO.
FWIW - on topic of rust removal and prevention:
If you live in a place where tools rust quick (due high humidity and condensation issues), preventing moisture from condensing on the cast iron is required. Simple blanket, wood, or cardboard cover between uses, and maybe an air circulation fan will save a lot of rust clean up time.
Furthermore:
When your neglected cast iron has developed rust in pores (yes, cast iron has pores due excess carbon); suggest sealing the pores by converting cancerous red iron oxide rust to black oxide. It is best solution to reducing cast iron maintenance.
I use one several similar spray products:
Loctite Extend,
Permatex Rest Treatment, or
Duplicolor Rust Destroying coating from the local auto parts store. They have a compound that converts red rust to black oxide, and leaves behind a thin polymer film. The products are intended to be used a primer under paint, and since I don't want film on my cast iron, use a different application method.
:First I scrape excess rust.
:Maybe use wd40 and coarse pad to remove any remaining surface rust.
eep clean with chlorinated brake cleaner to remove all wax and oils.
:Lightly spray rust convertor on surface, and use gray buffing pad to work it into pores. Wiping majority of excess off the surface with paper towel.
:When it has dried in 1-2 hours, I wax using same white pad as normal. It removes any film on top of the cast iron, but leaves pores sealed.
I repeat this treatment on cast iron any time I see rust forming in the pores of cast iron top, or if neglect has generated pitting. Did it once year living in Midwest states, and ~2-3 years or after any cast iron surface restoration here in Arizona. Thanks to this 'sealing treatment', the only rust issues I find are due highly alkaline sweat drops left on tools while being used.
YMMV