i picked one of these up locally for a good price

so i need some advice on how to take care of it

it says to take off the rubber thing and calibrate it with #7 or 10 or both, which i did

i rinsed in warm tap water, calibrated with 7, rinsed again, calibated with 10 and kept doing it until they were were both okay

so do i leave it without the rubber cap when i use it?

also, it says to never have the probe dry. what exactly do i store it in if i dont use it?