i use milk cartons for growing seeds in the house before the first frost. i also use them to pee in, then use the aged urine for fertiliser.
My grandsons came over today and i gave them all some gardening lessons and they joined in to help, digging and sieving soil, putting scrap food into compost bin and even pouring urine into watering can before i added water and poured onto the newly weeded beds.
Not finished yet.
Then we went to the fun fair :-)
yes, urine is just another asset that is being reused.