I use mine (and old fashioned cheapie version with only a 3 min cycle) with plastic and have had no
bad results... But I do check the water temp frequently and change it about half way
through the 10-12 cycle run I've found as being sufficient steeping for
most juices...
tobacco juices I will run longer - at least another half-dozen cycles with another water change at the beginning of the 3rd cycle...
I only had one problem with it early on when I went with an
'if a little is good, more will be better' mindset and ran the cleaner continuously with no water changes for, like, 2 hours... Didn't notice any plasticy flavor, but the heat must have burned off most of the nic and the vast majority of the flavor because there was almost no throat-hit and the taste was almost watery...