Best Tip: Ride your bearings until your wheels don't turn anymore (which takes surprisingly long) and then get some new ones. It's not wort the effort. I wasted too much of my Newbie days cleaning bearings when I should have been skating. Get new bearings for as little as R150 from First Nature.
If you have Biltins they might be worth cleaning because they are more expensive. Swirl them around in a bit of acetone until they spin freely, let them dry for a few minutes then put 1 or 2 drops (seriously 1 drop is enough) of Bones Speed Cream or any other oil (sewing machine oil is good) into each bearing. If the bearings have rubber seals make sure you remove them, the acetone will eat them. Biltins have steel seals that don't need to be removed.