I've cleaned several sensors with a kit

I've cleaned several sensors with a kit ... had both a cleaner solution and a sort of flat or paddle-type Q-tip like tool.

Dampened the paddle, wiped across the sensor a couple times, and it dislodged the troubling gunk or whatever. Wasn't too bad to do.

A friend's cam had a spot I couldn't get rid of as gently as I'm willing to treat a sensor. We took it to a local camera shop we trusted, and they said yea, sometimes things can be kind of stuck. And for those things they had a higher-powered cleaner solution. Watched him do exactly what I'd done, but with his cleaner ... and bazappo the spot was gone.

Neil