At the beginning of the season, stove ran good (6039 CORN & PELLET MULTIFUEL STOVE) they someone said to mix wood pellets and corn to get a hotter heat. ran good for a while.then started to build up in the fuel box like it does not burn up all the way. clean everything up and started back with corn and chick scratch. and it is still building up. and suggests why and what can we do to have it burn up the fuel.