I've taken a look at my duct work, square, old and needs replacing but for now it's here to stay until the budget allows for a new boiler. So...is there a correct/incorrect way to take it apart so that it can be cleaned? The duct work is hanging from the basement ceiling and with no insulation wrapped around it, it's very accessable. I tried the old shove the shop vac hose down there...I just dont think that's doing much. Any suggestions? I appreciate it, thanks!!