If the rebuild is similar to the ViVi Nova (meaning a wire wrapped around wicking) then I get a nasty taste if I don't follow that YouTube advice to take a match or lighter and burn the wire first, and wipe it down. Resistance wire comes out of factories that expected to sell to other factories for hair dryers, furnaces, and the like, so it's up to you to clean it enough to
vape.
When I forget, then when I get done cussing I soak the finished head in vodka overnight then rinse it off and let it dry for a couple of days. This is one reason why I make sure I rebuild heads before I run out of them!