Huh, timely post... I spent last night cleaning nuts and bolts in the kitchen. A lot of bolts are M10 x 1.5mm coarse thread. These are the larger nuts and bolts. The slightly smaller ones that you find sprinkled around the engine are M8 x 1.25mm pitch. In my case I decided to clean the bolts with solvent and a brass wire brush, since bolts have nothing internal. When it comes to nuts, they're harder to clean internally and they often show some signs of damage or rounding; I'm generally just going to replace nuts and washers with new ones.

Kurt

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- '79 240D - engine swap complete! Engine broken in! 28-31 mpg! Lovin' the ride!
- '86 190D (W201-126) - 2.5 NA engine, 5 speed, cloth interior, manual climate controls, 33-34 mpg (sold to forum member).