Cleanup Radacct table (Need Help)

[Jeff]

Seems like everyday from one upstream provider we use I get accouting record start and for some reason i get no stop packet on customers. I also use same radius with YourNetPlus and I am not seeing this issue with them. So it leads me to believe its something between I and GlobalPOPS. My question is mysql programming knowledge is not that strong does anyone know of a query I could run every so often that would cleanup the raddact table of records as such.

For example I would like to clear all records with start time greater than 5 hours old from the time the query runs with no stop time.  I have session tme out of 4 hours so there is not much chance that a user is still connected. 
At least that way my users online listing, etc won't be cluttered with old users on, and possibly be blocking a user access due to it thinking they are still connected.

I know globalpops is going to tell me this is latency on our network and not theirs. But if that was the case I would see several happen from the yournetplus network also.