Both Jack's methods he posted work well. You can also throw the pep in any kind of pan and put it in the oven as it is preheating, it will release grease and even fry itself. How much heat and how long , a little or a lot, just depends on your pep and what you prefer in the end.
My preference at the moment is to nuke it between paper towels but only for about 10-20 seconds depending on batch size. Press out some grease, let it cool some, then repeat as necs. This seems to extract a lot of grease without altering it much. If done correctly, the pep remains pretty much unchanged except the chunks of fat go away and even leave little voids where they were. The idea is not to let the pep temp exceed 140f. Over that, changes take place. This method is courtesy of RedNovember.
On the other hand, sometimes I heat the heck out of it. Bacon-ey, crispy, sorta hollows out and gets light, just a little black on the edges. So good it deserves it's own name. I vote for "pizzaiolo's candy". I can only do this when I am alone in the kitchen or it will never make it onto the pie.