Maintenance
In this section
What should I do before playing a euphonium that has been stored for years
Inspect it before forcing anything, clean the mouthpiece, and have a brass technician deal with frozen slides, damaged valves, leaks, or heavy internal dirt. A long-stored horn may need routine service even when it looks fine in the case.
What should I check on a used euphonium
Check the exact model and valve system, then test every valve, slide, brace, water key, and register. Cosmetic wear may be harmless; sluggish action, stuck slides, damaged valve casings, leaks, and uncertain provenance deserve a repair estimate.