I doubt your clipping out problem was related to cleat maintenence. in my 15 yyears or so experience with Speedplays I've found tht dirt in the cleat definitely will make it hard to engage. I've never found that it affects the release of the cleat.

And my maintenence routine is to squirt the cleat with a water bottle if it gets dirty, and replace it every 5,000 to 10,000 miles.