Adjusting tool for pots and IF cores
 

I have used plastic/fiberglass/ aluminum knitting needles for years to make adjustment tools I needed, when I didn't have the correct one, or mine broke.

Simply heat the plastic ones and shove carefully into a core, and let it cool. It will fit perfect. Be very gentle with heat and force on the cheap plastic ones.

You can sand or grind down ends on the fiberglass & aluminum ones to a flat blade screwdriver shape for pots, trimmers, etc. (Crochet hooks can work too.)

I only use the aluminum ones where the metal wont effect the tuning, as in IF cores.

I have been about 95% successful with this method.

I ran into one where the core hole was square in the ferrite, and took a tongue depressor and whittled the end down to fit. (Wooden swab shafts were too small.
Sometimes you gotta think outside the box. (But don't let your XYL taking her knitting needles.)