Ron,
I have been thinking about this and have a couple ideas that are not conventional, but might be effective.
You could use one of those gel products for cleaning electronics. It's basically a tacky firm of play-doh designed for pulling dirt out of cracks and crevices. The risk on this one is that it might push the dirt in deeper.
My other idea is to use an acne black head remover strip. You wet the strip,, put it in place, let it completely dry and peel it off. The moistened glue should penetrate dirt plug and bring ALL of it out. This would be better than the gel approach, and better than using any kind of tape - - which would only remove the top layer. I would think that there is no risk from the moisture as this camera should be "waterproof" or "weatherproof".
If all else fails you could still open the camera and push the dirt out with a dental pick or small gauge florist wire.
My 2 cents, ayor.
Larry