I bought two of them the other day from altsmoke.com . I didn't wash them.... first one I put HHV's Legend in it (Gandalf) and it was fine, never tasted what I would call a tennis ball lol.
The second one not so lucky. Put in HHV's Heavenly Tobacco (old RY4) and it tasted horrible. Didn't want to waste this delicious
juice so try to get through the first tank without tossing my cookies. Halfway into it , it's getting slightly better (but still horrible).
I think from here on in I will wash any tank I open before using. Lesson learned.... The tank itself is pretty nice though.