For the last month or so Iíve had trouble with sticky valves. I use Blue Juice and it usually works fine, but lately even after oiling, they havenít seemed quite as they should. I washed the instrument and particularly the valves but that didnít help much. The valves were reworked last year so they ought to be in fairly decent shape. In desperation, I tried putting some STP fuel injector treatment on and voila; they immediately began working like new. I only used the treatment once since it stinks like a refinery, but it sure did the trick. My question is, does anyone know of any adverse effects to me or the horn, which could come about because of applying this treatment from time to time?