Opportunity is missed by most people because it is dressed in overalls and looks like work. - Thomas Edison
was there any sort of sealant used on the ductwork?
Keeping a long story short....What is this stuff? How does one eliminate it? Interchange's position: The dryer is operating to spec - ergo, the issue is being caused by our inks and/or the garments we use, etc. so contact them. So, according to Interchange, THE CAUSE is not the dryer - it plays no part in this stuff's appearance since the dryer is operating to spec. Moreover, WHAT IT IS, suggested by Interchange, is either (1) the ink not evaporating in the chambers (thus making the ink the real culprit) and/or (2) I need to check with what the shirt manufacturer's put into their garments as that is what could be burning off and causing the black resin (thus making the shirts the real culprit).Sorry Guys I have been across the border!Here are some ideas, thoughts. This problem occurs and has occurred for a long time with ALL dryers!What does your vent configuration look like? How many, and what type off bends?What does your Vent Roof Cap Look Like (Type) Is it 4' above roof line?Does it Keep Water Out? Even On a sideways Rain? (I have seen this often)Your are not doing enough # in my opinion to get a heavy build up of Tar, in the amountof time, that you have had your dryer. I could be wrong, but I don't think so.It can be exhaust related, which is why I need to see the exhaust!On the MD8 (a very good dryer) they do not have a powered exhaust. It is not a problemif you have one to two bends and are running 50' total or under. If you have multiple bendsand/or you are running 50' or more than you will need a booster fan. I also recommend on anydryer to make the exhaust 2" larger than you need. It helps keep static pressure lower!Also make sure you have mesh blocking the roof cap. I have seen birds fly in open ones at nightto get out of cold/bad weather! and get shredded if don't get out before the fans get them.It is Not an Interchange problem, It is an Exhaust problem caused by any or all of the above.Winston904.3430848