Rust will occur on the surfaces of metals and must be removed for multiple reasons. Rust can impair material performance as it is a process that gradually removes material from the part. Rust also interferes with the welding process which is a critical stage in manufacturing the Chassis and the solar car as a whole.
Rust can be removed using sand paper. The coarser the grit, the faster the rust is removed, but the deeper the scratches are. For metal furniture or fixtures that you plan to repaint, you shouldn’t use sand paper coarser than 150 grit. For a car or metal appliance for painting, the lowest limit for sandpaper grit should be 220.