I intend to use a 8MHz pro-mini powered by a 3v Li coin cell. Obviously I'll remove the LED's - should I remove the 3.3v regulator as well?
Allan
Yes, remove the regulator. I wouldn't bother with the "solder wick" described in the article linked above, just swipe the components off with the heated tip of a solder pencil. They will still be reusable.
You can instead remove the resistor for the power LED, leaving the LED on for other uses.
Also appreciate that some Pro Minis are designed to be 5V\3.3V switchable and they can achive this by using an adjustable regulator and a resistor network across the regulator output.
The resistor divider consumes rather a large amount of current and need to be removed.