I haven't seen anything of that particular pattern so far... my strange shapes are a bit different... more jagged and rough I would say.
Right now I'm trying to find a way to round up some acetone and I'll see how that works out. If I can't get it taken care of, I'll be sending it to Flaminpyro to have a look at. He's offered to have a look already.
You can aslo use isopropyl alcohol (99%) and if you use a cotton swab, pull the tip a bit and roll it between your fingers so that the alcohol-soaked material enters the window and then turn gently... do the same this time with the dry tip to pick-up any fibers left and finally a quick blast of compressed air to loosen any prticles of dust and microfibers.
I hope that the gunk hasn't literally "cooked" on the diode window... there's little to be done then...
- Robert