I have some epoxy resin and hardener that is about two and a half years old. It still works fine, but I am getting toward the bottom of the jugs. My pump won't reach the bottom. I have new resin and hardener arriving.

Quesion: Do I go to hand pouring and measuring for the last half gallon or can I mix my new five gallon lot with the left over old resin I have and keep using my pump system? Same question for the hardener.
Thanks

Randy