[quote=Rustico]Just as a masking agent for the duct work you can put one of those jelly type air fresheners in the return air line or the FAU.[/quote]
I think there are two issues – one is odor and the other is color/staining.
Also, there are three kinds of surfaces – hard, semi-porous, and soft.
Hard surfaces (panelling, ducts, baseboard, cabinets) probably aren’t so bad for odor.
For hard surfaces you don’t paint, you will want to clean them so they aren’t yellow-ish and don’t smell. Probably don’t need to mask the odor if you clean the hard surfaces.
For hard surfaces you do paint, you will need to clean them for odor and oil-prime them them so the stains don’t seep through the paint.
Semi-pourous stuff ( panelling, drywall) will take on some odor. If you aren’t going to paint it or replace it, you may be stuck with a bit of odor. I would clean, oil-prime and paint all the drywall and panelling to remove the odor.
Soft stuff is the worst for odor and you can’t really paint it or clean it well. Best to get rid of it. If you have to keep it and a good cleaning doesn’t work, maybe one of those machines or air-fresheners or ozone filters will do.
