Hi Glenn,
Sorry for not replying sooner - I'll take a look at the code and see what I can do. Basically, there is a cron hook that checks through the exiry date values, which has a hard-coded CCK field name in it - you can change this to suit your requirements. If the product has expired, then we delete all the products from people's open carts.
The code is wrapped in a module with some other bits and pieces, but I'll take a look.
Dubs
