How do I look after a trombone slide?

A trombone has two slides and they are not the same thing. The hand slide, the long one the player moves, wants slide cream or oil plus a light mist of water, never thick grease. The tuning slide, the short one near the bell, takes slide grease.

Here is the habit that saves trombones: move the tuning slide even when you are not tuning. A slide left sitting corrodes in place (the metals genuinely fuse over time), and freeing one that has seized for two years can mean heat, and sometimes solder work. It is the single most avoidable big repair on any brass instrument. Once a month: pull it, wipe it, fresh grease, back in. Thirty seconds. Or bring it by and we will do it, no big deal.

The hand slide is more delicate than it looks. A trombone slide only works because two long tubes align perfectly, and a tiny bump or squeeze (set down carelessly, bumped on a stand, squeezed in a case) puts a ding in that alignment and the slide drags forever after. Our bench will tell you the trombone slide is the fussiest repair in the building, so treat it like the precision part it is.

If the hand slide feels sticky, it is usually just dry: clean it, lubricate, mist, work it. If it catches at one particular spot, stop. That is a dent, and forcing it makes the repair bigger.