look ive never not been able to clean even the dirtiest pipe in less than 30 (stoner) minutes....
dont use metal it will scratch glass...
Take a glass bowl that you can put your pipe in, put your pipe in the bowl
fill it with the highest % of ISO alcohol available/affordable to you... 99% isn't important but anything higher than 90% is great.
Submerge as much of the pipe as possible..
Let it sit for like 5-10 minutes, and just shake it/rinse out the nastier water inside the pipe.... after this i give it a good rinse with hot tap water to get any extra gunk out I can and I let it dry for a little (so the remaining water doesn't dilute the ISO)... i do this to get the bulk of the tar out, so I can focus on getting it squeaky clean later..
Now the bulk of the mess should be gone, and your left with a semi dirty pipe... (like urcas picture)
now you hold the pipe upside down, so the mouthpiece is going to the ceiling, and the bowl pointed to the floor.... Cover the bowl with your thumb and the carb with your index.. pour SALT into the pipe through the mouth piece(epsom in the $.60 container is great). Get a good amount of salt in there but not TOO much.
Follow up the salt with more ISO alcohol. Do all this over the sink, obviously. You should now have iso alcohol and salt, inside your piece with all the holes covered/sealed by your fingers.
Now shake accordingly. Up & down.. circles... whatever... it depends on what your trying to get off....
The salt will rub off the tar from the hard to reach places.. as the alcohol simultaneously breaks the tar down. The salt will not dissolve into the iso alcohol, and it wont scratch your glass.... so it is a VERY safe abrasive...
forget that 420 cleaner bullshit... iso and salt is safe, effective, and very cheap. Most people don't understand how to do it the RIGHT way though. For whatever reason..
happy cleaning