And how would RON 95 be dirty? RON numbers does not indicate the quality of the fuel. RON just indicates the 'anti-knock' qualities of the fuel. The quality is the same. It burns with the same calorific values giving the engine the same amount of power.

And how do you expect to clean your fuel tank by pumping RON 97? Cars have fuel filter for that reason and as long as you are not removing your fuel tank, you will not be able to remove any large sediments that is filtered by the pump before reaching the fuel filter.