I created a 22 pin edge connector. I noticed when I review my gerbers I see solder paste at all the connector pads.
In Altium Designer Summer version, the '4 Port Serial Interface' design example shows a rule to prevent the solder paste from being included on the edge connector of that design.
I replicated the rule in my design but I still see the solder paste placed on the edge connector pads.
use desolder wick (copper wire, not tinned)
then clean with isoprop. Alcohol + tooth brush
Areas that should not be soldered may be covered with a polymer solder resist (solder mask) coating. The solder resist prevents solder from bridging between conductors and creating short circuits. Solder resist also provides some protection from the environment.
you can set the solder mask expansion on the pads by taking the longest pad dimension, half it and enter that value in negative in the paste mask expansion.
i.e. for a 3mm pad the solder mask expansion will be -1.5mm.