Yes you must get the enamel off. The best way to do this I've seen thusfar is
to tin it. That is attempt to tin the enameled wire until the enamel
melts/burns/whatever off.

Usually then you got a nice tinned surface which will make a good connection.
In fact, in a blob of solder there is no atmosphere, so not only have you not
nicked the wire, or shaved any of it off, there will be less corrosion and the
sweating will go even better.

Mid-aged hillbilly with an engineering degree taught me this. Amazing what it
takes some times eh ?

JURB