I have used them over the years in some of the jobs I worked at.
It should work good on that crud. It may also leave real little dimples in the metal.
Very loud and it should not used on body metal without a lot of care.

Don


1967 GMC 9500 Fire Ladder Truck
"The Flag Pole"
In the Stovebolt Gallery
1946 2-Ton grain truck
1946 3/4-ton pickup,
1953 1-ton pickup
1957 1-ton flatbed dually,
1954 Pontiac Straight Eight
Of all the things I've lost in my life, I miss my mind the most!