While playing around with my Ambassadore cornet, I neglected to pay attention to my new Xeno. When I last played the Xeno, I lubed the valves with Ultrapure and forgot about it for six weeks! I pulled it out from the case yesterday and found all pistons stuck. I removed the lower caps and squirted some fresh Ultrapure and let it set for a few seconds. Luckily, they all came loose with no further problems. I cleaned each valve and re lubed and played the horn for about an hour. Seems OK now but it scared me for a moment. I guess the precision fit of the pistons in these pro horns may require more attention than the loose valves of my other, older, student level horns.