1) don't put a hot clutch away in storage on a wet day
2) you can use a piece wood cut to correct length or something to hold the pedal down enough to disengage the clutch for storage
3) If put away dry on a dry day, and you go and press it one a month, should be no issues..
4) sometimes, they can get SO stuck together that you can press the pedal to the floor, and watch the slave rod extend, and still the only thing bending is the clutch springs...not so good!
5) If you have to 'Free" clutch using the above 'brake' method, check your guibos after, since all the force is on them