Here's my approach. It's overkill, so water down to suit your needs.
a) add a field to the table called "completed". Set this to 1 when the user clicks on 'Save'.
b) add two fields; DateCreated, TimeCreated to the record. Prime these when the record is made. (ie use the Priming tab).
c) create a procedure (normal clarion source) which runs through the table, deletes all "incomplete" records "older than x".
I start the procedure, (using START, so it's on a separate thread) from the WebServer. This could even be a separate exe really.
Using the Take Event method you can start it say once a day, or as often as you like.
cheers
Bruce