A very good question Bai...
BUt the best thing to do is.. ki unna da antim sanskar kr dena chahida hai.. i mean unna nu AAg lga deni chahidi hai.. taki beadbi na hove..
VAise generally people dont realise this, and peolpe throw them in bins and all the other plces but religious calender contaisn pics, gurbani and other sacred things.. so thats BE ADBI...
the best thing is ki AAG laga diti jaave...