i rake the buckets from time to time. things i've found through experience are to be careful in summer time when temperatures are high and buckets can get a bit smellly and full of germs and the occasional rat. I tend to avoid supermarlets and go for local deli type shops, the type with nice bread and stuff. take note of closing time of aforementioned deli type place and be there once staff go home 10/11pm, end of the day is when all the bread and stuff gets put out. It seems they bag everything up seperate from each section of deli type shop, so once you get to grips with their system u are quickly aware of whats in what bag, you learn to sort through things methodiacally, avoid heaping bags onto the street and scattering contents - have a system use feel / touch open persuse stack to one side, have a defo pile and a maybe pile, stack bags u been through to one side of the bucket cos avoid staking bags on street police or passersby just get annoyed. avoid taking to much if you dont have freezer etc, check dates, and inspect throughly with torch etc as you go., leave no mess, wear gloves have a head torch, gas key, hat to avoid bin stink on your hair and have a seperate set of clothes and rucksack just for buckets cos smell lingers. i avoid anything with meat or fish in it, im veggie but even if i wasnt i dont trust how long stuff has been out of the chill cabinet (maybe good for dog food tho). also i have found that locked buckets have a triangular lock thingy that a gas key. the big yellow one fits onto and opens them up.
been stopped and person checked by police before and in scotland there is such a thing as theft by finding, but i think the police arent interested in taking someone to court for being hungry, just be polite say you dont have much money and they leave u alone.
helps to have a sidekick too, and be fast dont linger too long, lock up after you are done too
well thats my experience / advice i hope it helps someone