Just wondering how often a rainbow should be tore down a cleaned inside? Its only 8 years old but it gets used everyday. We do heat our home with a woodstove but I use a Kenmore canister with heap bags to clean up the wood dirt and ash dust but i'm sure some ash dust makes its way into the rainbow and past the water. It doesn't look to bad for 8 years old but its by no means spotless inside.

