The following is a real studio trick. As far as I know, I invented it. I don't know anyone else who uses it and it works like a charm. If you use it too, great.
I'm sure everyone here replaces their drum heads on a regular basis because of deep dimples. Dimpled drums are also very hard to tune. Many times you will start a session with properly tuned drums and by the time you get a take, they are trashed and ugly. I can help you solve all of these problems almost effortlessly.
Go to Home Depot and buy a Milwaukee heat gun for $29.95. Sit down at your drum kit and start on the smallest tom tom. Tighten the head to about twice as tight as you would normally tune the drum. Very high. Turn on the heat gun and make swirling motions about an inch above the worst dimples. As you swirl the gun over the head, the dimples will magically disappear! Sometimes you will need to re-tighten the head as you go, if the damage areas are really bad. No problem. Just tighten it again and keep working. In about two minutes, you can make an unusable drum head look and sound like new. No kidding.
Be careful to keep the gun moving all the time, or you will damage the head. I like to look at a light reflected off the drum head so I can see every little imperfection. When you are done, just tune the head back down and move on to the next drum. This will work on any plastic drum head, oil filled or not.
I have gotten so fast with this that I just keep the gun ready next to the kit and when I think the band is reaching their peak, I run out, tweak up the toms and grab the take. Works like a champ.
I even use the heat gun to tune problem toms. I have found that some toms (13"s especially) won't tune correctly no matter what I do. In these cases, I bring in the heat gun and make LARGE swirling motions around the rim area of the head to just slightly soften it. Presto! Tuned drum.