I realise I'm on dodgy ground here, as the sensible advice is always to take your instrument to a professional, to get it tuned up and so on. So I *don't* recommend copying me and fiddling with it, unless you have a calm and rational disposition and a good understanding of physics, or engineering; and if you do, only to make changes which you can reverse, to put them back as they were. However, I have no money for professionals, or to buy a better instrument, so I sometimes wonder how to improve the intermediate model that I have. My most recent experiment has involved adjusting the valves. Taking a few detailed measurements, I realised that all of the valves press down further than necessary and overshoot the correct position by about 2mm. A little research on the web told me that budget valves are often made this way, so that they can be adjusted if required. (If they were made too short, it wouldn't be possible to adjust them, so they are generally made slightly too long.) So I've taken a lot of measurements, and umm'ed and ahh'ed; filed down some plastic spacers to exactly 2mm, and added them underneath the internal valve felts. As a bonus, the valve travel is reduced from 17mm to 15mm, making the valves easier and faster. If the experiment doesn't work, I can simply remove the spacers; but I have a feeling, when I test it properly, that my cornet is going to play better than ever. Another thing I'm wondering about is plugging the main water key. The space where the water collects must disrupt the intonation on certain notes, and if the cork went up into the hole to partially fill the space, it would play slightly better again. Has anyone else made modifications like these, or does anyone have interesting ways of improving their instrument?