Removing denatured Crystalbond? I have some water-soluble crystalbond that is attached to silicon and, because of some overheating (to about 150 Celcius) during a final processing step, the crystalbond seems to have charred (white/grayish colour, see photo at the bottom) and is no longer dissolvable in water. Since this silicon is important and cannot be replaced, I really need to find a way to chemically remove this overheated crystalbond residue without using abrasives that could scratch of the thin SiO$_2$ coating on silicon.
Looking at the MSDS (see here), crystalbond is composed of the following

97% Nonylphenol Polyethylene Glycol Ether(127087-87-0) EC-No.
500-315-8
3% Polyethylene Glycol(25322-68-3)EC-No. 500-038-2

My question is: does anyone have any ideas for what crystalbond decomposes into around 150 C and how one could remove this overheated crystalbond residue?
Things I have tried (unsuccessfully)

Hot DI water (in a cup, and in a ultrasonic bath)
Acetone
2-propanol/ethanol
&quot;Piranha&quot; etch (asked a lab friend to do this, too scary for me!!)
Photoresist remover (lab friend also tried this)
Hexane
Dunking in LN2
Putting on a hot plate at 225C for about 24 hours
Burning under a 1100C torch for about 30 seconds

Any bright ideas, especially from organic chemists? All I can say is: damn this stuff doesn't want to come off.
Some examples of the residue below.
Lots of crystalbond residue on this Silicon wafer

Another silicon wafer with crystalbond residue. Less than the one above, but still significant.
Just a quick answer without looking too much into it.
You have been using a lot of polar solvents without any luck. The reason is that the molecule no longer has the groups that make it water-soluble because of the thermal decomposition. Only hydrocarbons chain remain. You need to use an organic solvent (toluene, benzene, hexane). Since you probably don't have access to a lab, I would try with gasoline.
Let me know if it works.
Cheers.