In a lot of cases especiallly if there is a little bit of filament stuck in it , if you are running a Cubicon Single Plus printer like I am and you get a clog you can actually heat up the hot end and the extruder assemble then shut off the printer and compleletly remove that assemble there is an area of all plastic to hold onto and the extruder and hot end can be cleaned and unclogged manually once its off. I know that you cannot do this with norrmal printers but the Cubicon Single Plus is designed that way.
As for other printers , the thing to do is once you do get it unclogged , get some nylot cleaning filament from Amazon (link coming later),... it is very expensice like $16.95 Canadian for 100 grams (I think that is the measurement in this case), it is like normal filament, but has ridges on it and you only use a foot as a time and I can highly recommend using it after each print). Also buy some little wire cleaning rods with 0.04 mm wire maybe 3 inches and an inch and a half metal handle for cleaning the filament entrance on the extruder mechanism.
If you do that after every print you will have no problems with clogs or jams in your extruder..... Russ Campbell