Carbon/thermometer

[Jedi68]

I am in the process of fine tuning my set up and I have a couple of questions .

1. For people that are using carbon a few days per month, what do you do with the carbon when you take it out of your sump. Do you throw it out? Do you rinse it and store it?

2. I just bought a digital thermometer from J&L and I am wonder where one would put the probe. Where is the optimal location that would give me the most accurate readings?