This Flyertalk thread cites an internal memo to Northwest flight attendants telling them to accept Delta drink chits, and no longer to accept Continental drink coupons. (Northwest’s coupons can also be used to purchase buy on board items, but they don’t take Delta coupons for that.)

Effective immediately, Northwest Flight Attendants may begin accepting Delta’s amenity coupons on all Northwest flights. A sample of the Delta amenity coupon Have One on Us is pictured below.

Please note that these coupons are about the size of a standard business card. The Delta coupons may be exchanged for one (1) alcoholic beverage or headset. Delta amenity coupons may not be exchanged for any buy on board food items. Delta amenity coupons should be included in the calculations under the deposit summary section of the FS-95 Sales Activity Form and deposited in the FS-93 Cash Envelope.

Note: Also effective immediately, we will no longer accept Continental Airlines’ Continental Currency coupons.

Flight Attendant Manual section 365.1 will be updated in the next revision to include this new information.