What about the electrolysis rust removal method?
It does indeed have its uses, but has the limitation that a workpiece of relatively large surface area [e.g. a mower deck]requires a
very hefty low voltage DC power supply to drive it.
The critical factor here is current density, in terms of A/m^2 of surface area. For a largish surface area, you really need something along the lines of an old electroplating power supply unit, which aren't all that easy to come by, in the right size.
There are a fair few used units [a Google search for 'electroplating rectifier' finds these] on the market, as many 'jobber' electroplating shops have closed down in recent times, due to environmental compliance and waste disposal issues.
But these tend to be way too large, in both physical and capacity terms, for use in a home workshop. Like 415V 3 phase input, and several thousand amperes DC output...
