I have a Venmar Constructo 1.5 HRV and would like to get some advice on cleaning the motor blades. I have not taken off the housing before and am not sure I want to do this in case I mess it up. Can a can of compressed air like the ones they use to clean the back of PC's etc work to clean the blades. They are not cacked/full of dirt but do have some dirt on the blades. Thanks for any info.