John Grabowski wrote:

Twist the wires together tightly with pliers and then twist on the wire
connector. You won't have a heat problem that way. Too often inexperienced
DIYers will just insert the wires into the wire connector and twist it on.
I think that the Scotchloks are the only brand that are approved for
non-twisted mechanical connection.

Ye Gads! I guess you learn something every day. I'm not an electrician
and I've always just worked on my own house, but I've never twisted the
wires first. However, I have always made sure that the wires are
securely fastened in the connector. The good news is that 20-years
later, I haven't had any problems. The bad news is that you've given me
yet another thing to worry about, but thanks anyway.