In January I shot several rolls of E6 slide film in FL and then mailed them to Kodak (Dwayne's) for processing. The mailers were long expired but I had read somewhere on photo.net last year that Kodak would honor all of the outdated PK mailers until December 31st of 2009. Based on that I accumuated PK mailers of various vintages. Some of them were PK-24 mailers but 24 exp. slide film is not easy to find and might not even be made any more. I called Dwayne's and was told that a PK24 + $1.90 could substitute for a PK-36 and that a PK-36 could also be used for processing 120 E6 film. Last week I sent a roll of 36 exp. E6 film in an expired PK-36 mailer to Dwayne's. The film came back today unprocessed with a note from Kodak that the mailer was expired. When did Kodak change this policy and how were we notified of this change? I understand that if you have a really old PK mailer with no expiration date that Kodak must still honor it but that too may have changed. I read that several photo.netters whoc are still Kodachrome shooters have been sending that film to Dwayne's but through Walmart and at a lower price. Is there a price advantage to sending E-6 film through Walmart to Dwayne's?