ORIGINAL: mkr
I try to keep it in mint condition by cleaning it often while running, using afterrun oil when I get home, aswell as cleaning airfilter and car at regular intervals while running. I'm also very very careful with dirt, and clean the entire motor completely before removing airfilter or glowplug with either denatured alcohol and a brush or bicycle cleaning spray and an air compressor. After a thorough cleaning I use car "bumper black" from Motip to make the black platic parts like new.