About the tackiness that forms outside the tubing at the vaporizer end of the tubing.People think silicone is impervious, but it is not. THC residues are strange and can enter hot silicone to an extent. The residues stay still after that.You can clean the outside of tubing where the stickiness has come through with Iso... and it will work only to show up again in hours.(even with non use) This is something that I learned to ignore, and the only cure is to cut down the tube an inch at a time to remove that tacky portion.. or just live with it...and eventually replace the tubing. 7th Floor Tubing (similar to Tygon) does not do this, but it also may not be ideal tubing for storage inside this device.
Interesting note about the tackiness. My theory:It seems worse when the tubing is cool.The reason is that the tube is then .. without heat in contracted state. The oils have exuded a tiny bit, as they seem to stay still. When you start to vape, the tackiness mysteriously vanishes. This is because the tube has expanded under the heat, and the material has "re-enveloped" the THC oils.. (silicone does have some permeability)
Silicone is somewhat porous, and when hot it expands, allowing some sublimate (condensate) to enter the tube, and bleed it's way through. During warming and cooling sticky substance can re-surface.
Pour 91% Iso on a paper towel, and grip the tubing firmly, and pull thr tube through a number of times... do it again with a fresh Iso treated Paper towel, and then wipe it dry. It will help, but will become sticky again later.
An alternative is a dusting of Baby Powder.
More about Herbie whips and residues at
http://fuckcombustion.com/threads/the-herbalizer.9116/page-62#post-521504