How are you keeping track of how old a record is? By a seperate field? if so you can use 'Now()' which is today's date and if a date is older than X days old call your delete routine.
DateDiff("d", nameofrecord, Now())
which gives you back a number and if that number is greater than or equal to the number X days delete that entire record
if you need me to give code I will, but I don't think I need to