i had this when i rotated my tyres, all i did was buy a rubber mallet ~ £2 and some copper grease
jack the car up (obviously) make sure its on some sturdy axle stands, back the rim from under the car (be carefully as you if you bang to hard you could knock the car off the stand) give the rim a few bangs then turn it 90o rinse and repeat.
once you've got the rims off use a wire brush to remove the oxidisation on the rim and hub, grease up before they go back on.
i cleaned and greases my nuts too at the same time