Friends,
I have been buying and selling tubas for over 40 years. Here are some tips for you to get the most for your instrument, and to make it more marketable:1 - Clean the darned thing! Once, I bought a tuba that smelled SO bad, I threw it in my pool and let it sit there for an hour. I still had to have it cleaned. Please, a good sonic cleaning will do your sale a WORLD of good!
2 - Get the dents taken out. A dented up tuba means you have not taken very good care of your instrument. I wouldn't even CONSIDER tuba that is dented up for my playing needs; unless I was planning on making it into a fountain, or flower pot.
3 - Get the valves ported. You cannot IMAGINE the difference this makes in it's playability. I have played many tubas that played badly, UNTIL I ported the valves.
4 - If you are not going to do a THOROUGH cleaning (see #1 above), at LEAST clean out the lead pipe and all the valve and tuning slides. PLEASE.
5 - If you are including a case (which does not increase the instrument's value, really), please make sure it is clean, inside and out. If your pet has made its home (nest) in it, just burn the sucker, and don't bother trying to pass it along.
6 - Including a mouthpiece does not really make the instrument more desirable; we all have our favorite mouthpiece. If you DO include a mouthpiece, for gosh sake, clean it out! NO ONE wants to see a year's worth of lunches in the throat. And round the shank, too.
7 - Be willing to negotiate, and take trades. This will make your instrument more desirable. We all love our tubas. Many times we (and I include myself here), over value what our tuba is worth. Buyers might not think as highly of that particular instrument. And as far as trades, who knows, the trade-in might really suit your needs. OR you might be able to sell it (the trade) for more than you took in trade (think of an automobile trade-in).
8 - Be willing to travel. I met a guy in Colorado once to get a tuba; he was from Ohio. We met 1/2 way.
My 2¢ worth; I hope this helps.
As always, your comments are welcome and encouraged.