Do Flues Need To Be Totally Spotless

[concord maple]

Just spent 5 hours scrubbing and pressure washing outside of flues to remove carbon. I treated 3 times with oven cleanerand let it sit for 11/2 hours each time and scrubbed but I still can't get it all off. During the season I cleaned once a week but no luck then either. Is everyone getting their outside flues spotless?

[markct]

why do ya want them spotless? no one sees bottom of the pan and as soon as you light a fire they get black! i clean them with a hose after the season to keep the carbon off as acids can etch the pans if you have 400 series stainless pans

[concord maple]

I am worried that over time I will start losing boiling efficiency if I don't get all the carbon off.

[PerryW]

I am worried that over time I will start losing boiling efficiency if I don't get all the carbon off.

I've used my flue pan for 23 years and I haven't ever done anything but run the (bottom) flue brush up and down each flue once at the end of each season. They lost their shiny-stainless look after the first boil in 1990. The efficiency and wood consumption appears unchanged over the years.

The inside of the flue pan looks new like the day I bought it.

[concord maple]

I've used my flue pan for 23 years and I haven't ever done anything but run the (bottom) flue brush up and down each flue once at the end of each season. They lost their shiny-stainless look after the first boil in 1990. The efficiency and wood consumption appears unchanged over the years.

The inside of the flue pan looks new like the day I bought it.

That makes me feel better. I spent alot of hours when I cleaned the pans during the season when I didn't need to boil but I was not able to get all the black carbon off. I was worried that it may cause issues down the road.