As it happens, the coffee-like stains that he and his colleagues had been trying to remove with fast-drying solvents was actually the solution to his problem, since they remained in contact with each other as they dried and preserved conductivity, but left about 95 percent of the light through the holes in the center, thereby making the screen itself almost fully transparent.
Also consider long-acting decongestant sprays or tablets, which help keep blocked nasal passages open when cabin pressure changes during take-off and landing. (Decongestant can be overly drying in airplane cabin air so consider saline solution, too).