I'll try to clean both LOCOs but I still think it's the bad pellets.The worst thing is moisture. More moisture, the more heat necessary to smoke. To clean I have read that scrapping is common. Keeping the breathing hole open is a must. For solvent cleaning you need to determine if the the pellet is an acid or a base. The litmus paper will tell you that. Use baking soda if acidic or coke if basic. It will neutalize the reaction and hopefully clean up. Most of the reading I have seen is the conversion to liquid. Insulating fiberglass is use in the unit to hold the liquid.It would be interesting to know what the stuff is made of.
I suspect a Hydroxide, if mixed with water if it feels slippery it is a base since it is dissolving the skin. If acidic it will burn.