I was looking at my four Baldwin BT223 filters today, and I called Baldwin Technical Services to interpret the date codes. It ends up that one filter was made in 2004, one in 2005 and two in 2006. I asked him about shelf life, and the advisor said Baldwin does not have a recommended shelf life, but they don't accept any returns (from distributors) that are more than 5 years old. He didn't seem to think the paper media would be compromised unless it got wet. The filters have never gotten damp or wet. Always stored in a dry, insulated garage. Are they OK to use for 1,000 mile OCIs in my Alfa, or should I buy new ones?