Ok, the silde of my Bach Stradivarius Gold Laquer trombone started to rust and all the laquer is being destroyed and leaving big patches of stuff that looks like blue-green warts. Basically the whole slide has rusted and a IMMENSE amount of brass abd laquer has been lost. Its now in the stage which i can actually feel alot of different between my friends trombone (same brand and model, except the rust). I don`t have enough money, so whats the cheapest way to deal with this?

Strip the remaining lacquer off of the slide, polish it with brass polish, and wipe it clean every time you put it in your case.

Is there corrosion on the inner slide as well? If there is.... i would get a chem clean, which would probably run you about $30 or more depending on where you get it done.

By rust, I am assuming you mean the red deposits. These red deposits are caused by dezincification, which is when the zinc and copper in the brass seperate because the zinc is being pulled out be acids, such as sweat. The green deposits come from the same thing happening to the copper. It is actually eating the metal of your instrument away, so I would recomend stoping it in the manner I suggested earlier and preventing it in the future with a brass polish (most of which have corrosion inhibitors which help somewhat) and by keeping it clean so that there is no sweat or moisture on the outside of the slide. Granted, it will get wet when you spray it or if you sweat on it, but it takes time for the oxidation to take place, so as long as you wipe it clean every time you play, it`ll be fine.

Ok thanks, i got confused with the red or blue part. So how do i strip the lacquer off? Hot water? And about the brass polish, does it get the rust off? And regarding relacquering.

You might want to play with gloves too. They will protect the metal and give your horn a longer life.

To strip the lacquer, I would rough it up slightly with 200 grit sandpaper, then I would finish removing it with 600 grit. This will remove the lacquer, but almost no metal. It should also remove corrosion (rust). After this, you should have a raw brass finish. I would give it a polish with brass polish to inhibit rust and tarnish, and then you should polish it periodically (like once a month). It will slowly develop a brownish patina, but this will easily be removed with a quick polish job.

On the subject of corrosion: Brass is made of two different metals, copper and zinc. Copper oxidizes (rusts, corrodes) and forms a green crystalline structure called copper oxide. Zinc does the same, except that zinc oxide is a red color, similar to that of iron oxide (regular rust). These corrosive deposits that form on your instrument are actually chemical changes to the metal. The metal is being taken out of the instrument and turned into different oxides, so it is best to prevent this if at all possible. When the instrument tarnishes, the metal is bonding with particles of dirt that can become caught in the relatively porous surface. Brass polish simply breaks these bonds and pulls the dirt away from the metal.

As for relacquering, you could do it, but it would cost money and a relacquer job never works as well as the original lacquer. I personally hate lacquered instruments, so I wouldn`t ever consider adding it to my horn. But if you really need to have a shiny horn, then have it relacquered by a reputable shop that specializes in instrumental finishes.