J.L.
Depends on how bad the rust is. If it's surface rust, then it's not much of a big deal, and will come off pretty easily. If it's pitted and oxidized past the paint, then you won't have an easy time of it. Commercial rust removers can be found at your local Home Depot, Lowes, etc.
If the rust is deep, you can 'sand' it off with steel wool. Get two grades, one kind of course, one extra fine, and use the course first, then the fine for finish and touch up.
It will now be shiny metal and will need to be sealed with a primer and then coated with appliance paint.
All of which can also be found at your local home improvement store.