Removing Mill Scale

[motorhead]

I like the vinegar method for several reasons.
1. it is less costly
2. less hazardous
3. easier to dispose of (I dump it on the weeds out back)
4. it works fairly well. it just takes longer is all.

Here are some things I have found to make a difference in using vinegar
1. For some reason, heat and light seem to make vinegar more "aggressive" on the surface of the metal, thus it seems to work a little bit better/faster if left out in the sun.
2. vinegar is available in different levels of acidity. Regular vinegar is usually 5 percent, pickling vinegar is 6 percent, and cleaning vinegar is 30 percent acidity.
3. vinegar will also etch/remove the zinc off of galvanized metal so it will take paint.

WARNING!!!!!!! IF SPILLED ON YOUR CONCRETE FLOOR IT WILL EAT INTO IT VERY QUICKLY!!!!!! (don't ask how I found out that even regular 5 percent vinegar will do it to it ).