Original A212CW AC Air Filters

[firstgenaddict]

Filter paper is impregnated with formaldehyde and other chemicals which is probably what causes the yellowing, although papers manufactured before the last 15 years used a much more caustic/acidic process to bleach the fiber, which causes yellowing and deterioration. (think old newspapers)
I had 200 tons of waste filter paper bales from a DANA/WIX plant, it would give you a headache just being around it for 30 min. It was almost impossible to get rid of, I sent a load to China, they said NO MORE, I ended up selling it to a company that manufactures roofing felt.