(Original question was about how to clean a thick layer of grease and dirt off
some old turnbuckles with minimum manual effort.)

Just as an update to folks...I ran one turnbuckle through the dishwasher. Did
well at taking off the surface crud, but it didn't really shine up the metal.

Going to try the rock-polisher next. My wife has a small one, with
buckshot-sized media for cleaning metal for jewelry work. Think the media is
too large, so I might try (unused) kitty litter.

Ron Wanttaja