I have first hand seen more than 1 lighter go from non working to fully functional with the addition of quality butane.

Ronson being the culprit of many clogged lighters. I know one trick for badly clogged colibris is to take a VERY fine syringe needle(attached to syringe) filled with ZIPPO fluid. Light it and it normally will burn off the clog. I have not tried this before but it has been rumored to work. I only use good fuel in my lighters.