i bought a conn cmel by mistake and it also was like that what i did was take all keys off, remove all pads and clean cups out. polish the keys seperatly on my buffing wheel and some jewelers rouge, don't know if i spelled that correct. after i got a kitchen garbage can filled it with boiling water added 2 cups of baking soda and plunged the horn body in the water with a piece of aluminum foil shinny side touching the horn. it wlll smell like tarn-x working , stinks, but it will remove the tarnish and now you will only have to hand rub to a shine. replace springs needed and put new pads. this will be a short 15 or 20 hours of work. ha ha hope you don't have anything bent or frozen and if you need springs good luck if you dont have the tool to pop them out. when you finally get to play it they are ok sound but i wish i could sell mine can't have tried nobody will even bid and it's in almost mint cond. now. and so is the case. good luck