If your filament is not flowing out of your extruder like in the picture above then this instructable is for you. In this instructable I will go over how to clean your hot end VIA the "Guitar String" method. This is not the method that Makerbot will recommend, They prefer the soak it in acetone over night method. But who has time for that?
Step 1: Take Apart Your Extruder
If you are unable to take apart your extruder to the point were it looks like the one in the picture above, Then maybe this instructable is not for you. Rather than go over the steps involved in taking apart the extruder I will just link you to another instructable that does just that.
Step 2: The Tools You Will Need
This method of cleaning your hot end is called the "Guitar String" method because most people use guitar string. I however do not, A far cheaper and therefore better option in my mind is to use "TUFF TIES" as pictured above. You can find them in the gardening section of most stores. You will also need some pilers to cut the wire. Before you start you will want to strip the plastic that surrounds the wire. It is not nearly as hard as it might sound, Just don't be afraid to use your nails. That being said if you happen to have guitar string lying around feel welcome to use that also.
Step 3: Preheat Your Extruder
You will want to preheat your extruder so that the plastic that is blocking the hot end will become soft. Once your extruder is up to temp you may begin.
Simply insert the wire into the hot end as pictured above, then remove the wire. When you remove the wire you will see that plastic as stuck to it, simply cut that part of the wire off and rinse and repeat. You will know you are done when you can insert the wire into the hot end and pull it all the way through and not have any plastic on the wire.
Step 4: Put It All Back Together
Now that you can pull the wire through that hot end without any plastic catching onto it. You can start to put the extruder back together. Once you extruder is back together and seated comfortably on your printer try and load your filament in. it should extrude straight down if you have done the "Guitar String" method correctly. If not try again. This method has yet to fail me (Knock on wood). Once your filament is extruding in straight line go ahead and try to print something. If you print fails your problem lies else where.