http://www.tiaowiki.com/forums/xbox-360-hardware-talk/83850c-v2-cutting-the-pcb-and-using-the-conductive-glue/msg680/#msg680
You might have to use boiling water to get rid of the conductive glue, along with other chemicals I guess. Try boiling/hot water first.
If continuity exists on all the pads in black, then it is fine (except for the ones with X). If JungleFlasher/BIOS/Xbox 360 can detect the drive, it is fine as well. You can try adding more glue but it shouldn't matter. Reflash the drive with iXtreme LT v1.1 or stock firmware if necessary.
Try to test your drive using all of the non-burnt Xbox 360 discs you have.