It reminds me of cigarette smoke but I think its just time, dirt from over time. Some of it has come off with just light cleaners I have, but I am not going to push it I don't want to harm it in anyway. It looks and runs so well and thats the harmony I like!
@Charles(electrolux~137)... Did that product completely remove the nicotine staining off of the hose? If so, Id like to get some to remove the coloring on my xxx hose that I bought off of ebay!