I have a older bike that the stem has worn paint. The paint LOOKS good but does not protect fromt rust which I found out after cleaning it up a little and having some surface rust come up on the thin parts.

Can someone tell me what kind of flat clear coat I can use on it to protect from rust but keep the original look? Link to specific brands and type would be majorly helpful.

The original paint is flat black with decals in good shape. So the clear needs to be flat for sure.

Can I just use a scotch brite to prep it before spraying?