There was a thread on this about a year ago or so, I now remember. I am one who finds that accelerator seems to loose its punch over time. I use it sparingly, using a needle eye tool to apply it, and a bottle lasts a long time- well over a year, so I guess it might indeed loose some volatiles.
I wonder what is really in that stuff. If it is fancy organic chemical stuff it is beyond me, but maybe it is pretty simple stuff.