I agree, toss it and fill a new one. It is hard to give up a carto that is working even if just ok, LOL, but when I do they are always burnt. I think anytime the carto is not working very good, or harder to draw, it's already burnt. Thats been my experience.
I just took a new one apart after 10 puffs and guess what, the diapers are already scorched, Even lf you don't taste it, the diaper I think "cotton" is up against a very hot coil and starts getting scorched immediately no mater how wet it is. The theory of heating water in a paper cup does not apply, put the paper cup on a red hot coil of an electric stove and the cup will burn, same as I can hold my finger in a flame for a little while but if I touch the red hot coil of a stove I burn immediately. I am sending a piece of the cloth to be analyzed at a lab.