Over time, a Fume Extraction System my build-up residues and/or particulate on the hoods and ducts used. The rate at which the residue and/or particulate will build-up depends on a number of factors as well as how much the system is used. While this build-up may be unsightly, it has very little effect on the performance of the system, except in cases where the build-up of residue and/or particulate is so great that the opening becomes restricted.
To clean the residues and/or particulate build-up from the hoods and ducts used, you can use a cloth with a gentle cleaner to wipe down the surface of the hoods. To clean the inside of the ducts, you will need to disassemble the ducts and carefully pull or push the cloth through the inside of the duct using a drawstring, rod, or similar method.
It is important to note that depending on your application, the residues and/or particulate that come from your application may contain hazardous substances and you should be aware of the required safety and disposal guidelines for your area.