DIY cleaning of 70-200 f/2.8 L IS II - experiences?

When I went to Antelope Canyon, I ended up with sand completely covering me and my camera & lens (24-105L).  They shovel sand up in the air to create those "beam of light" photos that everyone wants.  Small breezes take the sand everywhere.  At one point, I found myself standing under a sand waterfall, with sand raining down from high above in the slot canyon.  I was not amused.

As soon as I got out of there, I did some careful cleaning, and used a toothpick to remove the larger boulders between the rings, etc.  Still there was some grinding with one of the rings.  Since I was in the middle of a vacation trip, and it was the only lens I had with me, I kept on using it.  I noticed the grinding became less, and eventually went away completely after a few days.  The lens worked perfectly since then and never had any problems.

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- Bill