Home made charcoal added directly into the product for aging is a great way to impart new and/or unique flavors. I make mine in one gallon paint cans. Go to an auto body shop and buy a one gallon, UNLINED paint can. Be sure it isn't lined! All hardware or other paint stores will usually only have lined cans.
Cut your wood of choice into 2-3 inch lengths, and chop them into smaller pieces. I say chop because the rough surfaces are better than the smooth surfaces of cuts. Fill the can halfway with loose wood chunks, tap the lid on tight, and punch a dozen holes in the lid with a screwdriver or scratch awl or something. You can use a propane heater, an electric hot plate(finally! A use for that hot plate you bought for your first still...) or simply toss it into an open fire. Give it a shake once in a while, and when you no longer get thick smoke from the vent holes, pull it out of the fire, or off the heater device, open the can, spill the contents on the ground, and douse it with COLD water to stop the burning, and to create the billions of tiny fissures that will increase the surface area many times(effectively making it activated charcoal). This helps clean your product, and transfers the flavors quickly. Or, you can let the charcoal cool in the closed can for 24 hours; this will not have the scrubbing effect of the activated charcoal, but it will have an even more woody, smoky flavor.