Any ideas on decorating old trombone?

use it as a trellis for a climbing plant.

A plant would be beautiful inside it.

I'd do it up for Christmas! Polish it up real good and seal it against tarnish. After dry just use Christmas flowers, etc. to apply . to the slide. Then figure out how to make a stand for . it or where . you'll put it. If hanging it, hang on a slant.

My Grandmother played trombone with the Fadettes of Boston starting around 1915. She died in 1981 and I inherited her trombone. In memorium we hung her trombone in our guest room above the bed. We found the “hangers” at Bed, Bath and Beyond in the curtain tie back section and worked beautifully.