Molasses sure does work but for heavier rust. Vinegar for lighter rust. Usually a few days to a week followed by a cup or so of pool acid sloshed about for no more than a minute. Rinse thoroughly, then rinse again then fill with water and add a cup or more of bicarb soda to bring Ph to neutral. Dry the tank thoroughly then add a cup of penetrating oil and coat liberally to avoid further rusting. I use penatrol and it will never rust
Paint is personal choice. Powdercoat works and is not the nasty finish often claimed. Google powder coat and you will find the urban myths about powder coat busted
Powdercoat is a polyester urethane
2 Pac is the one many say to use. It's still nothing like the enamel of the original frame but will outlast you and me. Like powdercoat, it's a polyurethane and is a thicker than enamel finish. I usually have my frames painted in 2 pac with the addition of a flattening agent to take some of the bling out
I got this from the internet
Today, polyurethane coatings are applied using water-borne, solvent-borne, and high-solid or powder coating systems