I goofed. I left the parts I was cleaning in the parts washer with some ZEP commercial degreaser diluted with tap water and this happened:


Now I have extras of all of these pieces except the alternator brackets. One of those is steel and wasn't affected as much but the other is aluminum. I'll certainly use the extra upper timing cover I have instead of reusing this particular one. These are off an early M103.

So does anyone know what exactly this is and how best to clean it? I'm assuming the degreaser was too harsh on the aluminum, I'll use something else in the future.

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Current: 1975 450SEL, 83 300D, 88 Yugo GVX, 90 300D OM603 swap, 91 F150 4.6 4v swap, 93 190E Sportline LE 3.0L M104 swap, 93 190E Sportline LE Megasquirt, 03 Sprinter, 06 E500 4Matic wagon.