I was recently given 8 1 gal. bags of Kodak HCA. I note that it expired in 2009.
As it's in the plastic bags rather than paper my gut says it's still ok to use.
Any opinions?
It's an ISO 9002 expiry date and has little to do with reality.
there's nothing in HCA that will expire that fast, it's essentially Sodium Sulphite solution, dry it' keeps for years.
However ISO 9002 is supposed to ensure good stock control and prevent items being stuck at the back of a shelf growing old with fresh product being put in front of it.
As long as the powder is a powder and not a caked mass it will be fine. A few years ago Kodak started putting a generic expiration date of three years on their powder chemistry and two years on their liquids. This was probally to aid stock ration and had no real science behind it.
I've seen some people get into bidding wars for expired packages, buying them for more than it costs to get in-date ones, on the local ebay clone here.