How To Clean Ring Lands & Re-ring Pistons

20 minutes is pretty fast. Cleaning products are not like they used to be. When I started working in motor racing in 1984, it had products that after 1 hour the engine block was completely cleaned of all residues, oil, paint, ...
a fairly easy method to use at home is to spray sodium bicarbonate with compressed air.
and in 2003 at PSIMotorsport (Porsche FIA GT race), after 40 hours of operation, I clean the piston head with the projections of coconut chips, through the spark plug hole, valves closed, and after with a vacuum cleaner clean all the combustion chamber.