Game plan

So here's my idea and id like any feedback.



So I have my grandmas garage which is about 750 sq feet and I'm planning to fill it to the door with shred. Since prices are so low right now Ill hold onto it until they rise back up, or until I can't fit anymore. Than I'll get a 40yd dumpster from my yard dropped off and fill it up. My questions are how would I avoid theft? Do your yards have lids on the dumpsters they deliver? And how much weight should I expect a full 40yarder of normal everyday scrap such as appliances, bikes, weigh machines, duct work, random piping, chairs, and so on. Thanks a lot.