But there appears to be a national shortage of trumpet valve oil (funnily enough, however, no shortage of trumpet valve oil images on Google...).
Chris has been to the local music shop twice now to try to buy some so that Aidan can't use the stuck valve excuse to avoid practising his trumpet.
Not only does the shop not have any, but the supplier also appears to be having trouble getting it in.
We might have to try a music shop further afield. The trumpet isn't sounding too bad when the valves are working properly. And Aidan is on the verge of making it into the school band. I'd hate for a lack of oil to be the thing that stops his promotion.