Hello. I have a BR 1200. I think I have an internal dirty gain control. It sounds like a typical dirty control when turned up and down and sometime I lose gain output and regain it when tapping the knob or turning it. Would it be wise to remove the control knob and use a cleaning solution to clean it, like a commercial spray that works itself inside ? If so, what type of cleaning solution to use and what method would be best, or what would be the best method otherwise ? Thanks.