Here is my door clips....super simple but work like a champ.
http://i1074.photobucket.com/albums/...psomhmf4sh.jpg
For cleaning PTFE tubes I would suggest getting the proper sized drill bit. The issue with using a hex-wrench is that it is different shape than the tube, you could potentialy deform the tube by cleaning it like that.
A drill bit is round like the tubes interior is supposed to be. Not to mention a brill bit is designed to remove material from a hole, the channels in the bit will help alot to that end.