One way to alleviate the problems of mattress indentation is to flip the mattress on a regular basis. This is not a solution that can be used with a pillow top mattress. With a pillow top mattress a pillow-like layer is attached to the top of the mattress. While it can be rotated head to foot, it can not be flipped over. To remove indentations left by regular wear, it is necessary to periodically fluff your pillow top mattress.
Periodically flip the mattress from end to end, putting the foot end on the headboard side, and then reverse it the next time. This will help reduce the necessity to fluff the mattress, which can cause stress to the fabric.
Read your mattress's warranty along with any cleaning or care instructions that came with the mattress. If your mattress is currently under warranty you do not want to do anything that could void the warranty.
Remove all the sheets and mattress pads from the mattress. Vacuum the outer surface of the mattress and pillow top, using a canister vacuum with a hose attachment. Before fluffing the mattress you want to eliminate as much dust as possible.
Remove the mattress top from the mattress if it is a removable mattress top. If it is, take it outside and hang it over a sturdy clothesline.
Beat the mattress top with a broom handle, moving all around the pillow top's surface. If the pillow top is hanging on the line, do this outside. If it is on the bed, do this on the bed. It should take about 10 to 20 minutes to fluff the pillow top.