Applying diamond chrome with PC materials can help with buildup. Other mold coatings may help to minimize buildup and improve mold cleaning.In some cases with buildup, adding vacuum to the vents can improve the overall ability of the mold to vent. There are ways to do this with seals at the parting line but in some cases just adding a vacuum line to the vent relief can provide good results. Connect the vacuum line to a vacuum generator and use a mold closed switch to actuate the vacuum to draw the volatiles out of the vents.