A way back when I was a young sprout, my pop who was an old journyman mechanic taught me to pull the plugs and clean all the passages. Back then when you bought a carb rebuild kit it would have new lead plugs included. Quite often the carb cleaner doesn't get into the corners of deep passages. Much of the time I still try to pull the plugs if it looks like I can't get in to the passage with a pipe cleaner and solvent.
I've made up aluminum plates with a taperd hole that I can use to form new plugs. If you drill the hole small then work the bit around to taper the lip some you can make a pretty good tapered plug. A soldering iron will melt enough lead to fill the hole and with it you can shape a fairly good rivet head. A good rap on the table will usually dislodge the plug from the mold.
Denny Graham
Sandwich, IL

Denny G
Sandwich, IL