For my grill, lenses, front turn signals, and head light surrounds, and a few other items I waited until my (now ex) wife went to work and ran them through the dishwasher. Cleaned them up nice. I ran a load of dishes after to help rinse the dirt and stuff out of the dishwasher. Win-Win.
I had one grill that the dreaded prior owner had rattle can painted. It looked awful when I got it, peeling and faded. I found a stiff bristle brush and went to work on it. Once all the paint and dirt (some painted over) was off it looked great. A little careful wiping with acetone cleaned off the stainless/chrome strips at the top and bottom.
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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)
MEPR: Man, my 4x4 makes all other LUVs look good