1Click Offers are purged daily.
When configuring a 1Click Offer in CBX, there is a field for an expiration date. This field defaults to 30 days from the current date and cannot be longer than one year from the current date. CBX looks at the expiration date (stored in ONECLKOFRS table) of all active offers daily. The system purges any unaccepted offers where the date is in the past.