I use a turkey baster and transfer to an old jug with the top cut off to get the oil out, and then wipe out the bottom with a rag if there seems to be anything in there I can't get out with the baster thats worth the effort to use the rag. At least in my filter canister, the part you wipe out is on the dirty side of the filter. A few drops of the old oil isn't the end of the world, theres a bunch of residual in the rest of the engine after a drain anyhow, and the rag can get messy quickly. However, just getting the filter out usually ends up making a mess, so whats a few more rags?
