Small bumps can be leveled with a straightening hammer and hand anvil. If there are corrosive holes in the body, it is recommended, depending on the size of the damage, to replace the part in the kit or weld a sheet of tin.
Straighten small bulges with a straightening hammer, resting against the part on the opposite side with a manual anvil. It is not very hard to hit with a hammer, because otherwise the tin expands and ceases to be smooth. Straightening to produce, moving evenly from the edges to the middle.
Aligned surfaces should always be checked by hand to find out if the desired shape is achieved. Small irregularities are primed later. After straightening, carefully remove rust and remnants of old varnish from the repaired surface. This is done with either coarse sandpaper (grain size 120), stretched on a grinding wheel, or grinding plates on a convex disk. The linings and plastic parts located next to the damage should be pasted over with adhesive tape so that they are not accidentally scratched when the tool slips off.