artist

I am having trouble with 2 pencils which will not advance the lead without a lot of shaking and persuasion. The lead is advanced by means of pressing the button on the top of the pencil. Normally the lead freely falls out of the tip of the collet. Any suggestions on a fix before I ruin these...

This is an unknown blank received in a bag of blanks at a MAPG in Richmond several years ago. The kit is a 2mm Elite. Since there are not brass tube or extra ornaments the pencil weighs in at 0.5 of an ounce.