I’ve used my bench towel more than a few times. Then found a
scrap of phenolic tubing at a plastics supplier (was in the scrap
bin, but they didn’t know where the actual stock might be) that
happened to be close to the size required to fit tightly over the
square tweezer handles. A little effort made that work. Still
not perfect. Part of it is, as someone noted, that the carbide
tips I use for platinum work are wonderful heat conductors,
leading the heat right to the handles. But that’s not all of it.
Just the flame itself is often close enough to the handles that
it’s heated directly. One poster suggested titanium tips. Thats
a very good idea, especially for gold and silver work. They can
even be longer than the original types, and still work, with some
minor modification. I don’t like titanium for platinum work
though. Too easy to get it hot enough to burn, which gets
spectacular (Been there, done that, burnt the T-Shirt).