i rince my pt2 really well with super hot water, be careful with the washers in the top and bottom pieces (lost one of mine first time i cleaned it Lol) unscrew the atomizer pull the grommet off of it and wash it, run water down the center tube of the atomizer for a bit, blow it out, run water through it again. then dry everything off really well and blow out the head.. if you like you can pull that center post and see if the coil is really gunked up. If it is you can dry burn it if you like.. Just use really short bursts and take your time. AFTER each fire blow the coil off and let it cool before firing again.
https://www.youtube.com/watch?v=YQQafvfc8gU
It will take a while if the wick is still wet. Use a Qtip and some paper towel to dry it the best you can by pressing down on the ends.. Brush the coil off with something VERY gently or you can run it under water again after dry burning.. but then you have to dry the wick again or you get a water hit and that's not really that tasty.
DON'T USE SOAP!
letting it sit in alcohol is ok, but it will give your wick an alcohol aftertaste for a bit.
Pyrex and stainless steel are made to not hold onto smells or flavors. The Protank 2 is made out of Stainless steel and Pyrex. The parts you have to worry about flavor sticking to are the coil/wick and the washers and gromet. Clean them and you have no problem. It takes me about 10 minutes from the last vape on one flavor to the first on another, if I take my time with it.