I use rifle brushes and pieces of steel round stock drilled and tapped to screw them into. Most gun cleaning rods just aren't strong enough unless you buy the really expensive ones.

To soften the grease before you use the pressure washer, mix up a strong solution of Trisodium Phosphate and water, and brush it on liberally, then wait a few minutes before pressure washing. It's the powder that's used to clean grease stains off concrete shop floors and it's MUCH less expensive than commercial engine degreasers.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!