Hi Ian.
I have had the opportunity to have a free sensor clean at a few shows, do watch the ‘technician’ first, some of them are good, some not so much especially when they are peering out over an overwhelming stack of cameras to clean, the well organised ones stop taking cameras when they have reached a set number so they don’t have to rush through them and that is it for the morning, or day and you will get yours back at lunch or close of play! No rushing set time for each sensor. Some cleaning booths are out of the way, behind a screen etc, some just in the corner of a dusty show hall with Joe public flapping around near by.

???
Just observe a bit before handing over your camera to what could be the local exspurt, ex being a has been and spurt a drip under pressure!

I clean mine at home when I find dust, I can control the environment, and have as long as I want to do it right. I only use an arctic butterfly brush now, I used to use wet swabs, never done any damage.
Cheers, Graham.
Ian_of_glos said:
Alternatively you might find that you can have your sensor cleaned for free at a photography event in your area.