On about half of those occasions either the brush would come
out of the metal stem or the whole assembly would detach from the handle
and fly across the room. Not happy about this.
I have a 5D that has seen a fair bit of use - and as I don't have a spare body - lenses are often changed.
After well over a year the "visible dust" issue has really gotten out of hand and I had to do something.
Living in a magic but unpopulated place like Tasmania, choice is very limited. There is no local service centre for Canon and the local camera "specialists" are very happy to clean your sensor but won't garuntee their work - - If they break your camera you pay for it ? (But they are happy to charge you for their "service")
Canon service requires shipping and many weeks without the body.
So after much rumination and frustration I broke down and bought an Arctic Butterfly 724 from a local dealer. Cost in Australia for me was AUD$189.00
I wasn't entirely comfortable with spending that much money on such an item but I went home happy that I'd at least arrived at a solution - dollars be damned (and or burned).
Setup the workspace. Double checked the 5D manual and read the VisibleDust website (which is not the easiest portal to navigate, IMO) and their "slip of paper". Opened the cap and fired up the little motor AND . . . the pointy end of the whole business - the "ultra clean" brush head - flew across the room!!!! (BTW - I only found this thread AFTER the debacle.)
The 724 is going back for a refund tomorrow. A huge waste of time - very unimpressed.