What do I do with old insurance/pension payment slips?

I have a box full of them for various reasons. The pension payment slips I kept receiving even though I am exempt from paying pension, a few insurance envelopes are from when the administration refused to believe I am a student with no income and kept sending slips with large premiums. Unfortunately, I also have a bunch of payment slip envelopes because I keep missing due dates and end up paying only when I'm sent a second conbini payment slip (payment via ATM is not available in my city).

I retain all payment receipts, of course, and other letters where they say I need to keep them for 5 years and such. I also know I am not to throw away the blue booklet you get from the pension division. But do I need to keep the stacks of old payment slips? Or can I shred them?