You mean rims? To take those off, you un-screw the 4 or 5 lug nuts under the hubcap. You can then with a power grinder (or by hand if you wish) grind the rust off the rims. You will need to take the tires off the rims to do that (a garage shouldn't charge more than $5 to take it off for you). You might even get a garage to grind the rust off for $20 or so, much less than the $60-80 for a new rim.