Bill laid this down on his screen :
When you say paint, what with and inside or outside the wheel? Or is this
referring to painting the edges, or more, with sealant.

No point to adding it to the outside, it needs to be inside. The
problem with alloy rims, is that the salt and water corrodes the alloy,
causing a poor seal to develop between tyre and wheel rim. The
corrosion needs to be cleaned off down to bare metal, then the bare
metal painted to protect it.