The reason i ask is because i had my as5 in my car for about a year with out knowing that it was in the car. During that time the temperatures were between 100F and -10F. At the same time i had another as5 that i was using which was kept in my room for about same time and around 68F. One day while cleaning my car i found my as5 and used it on my rig in which the paste was very hard compared with my as5 which was stored in my room. I think extreme weater like cold, hot, humidity played a role in breaking down the components in as5. I know that some of you might disagree. You might say that as5 is made for extreme temperature changes.
If your as3 has not been through tough weather i c no reason not to use it but hey a new as5 is around 10 bucks.