First thing you'll have to do is start up a blank canvas map of whichever map you choose to perform this glitch on. Once you've chosen a map with literally NOTHING on it, start going down the list and spawning only one of every object (yes, every weapon, equipment, scenery object, ect.), besides goal objects and spawns, of course. While you are spawning the items, now remember, this is the most important part, press the X button twice while holding the object to bring up the item properties menu. Change the Run-time Maximum to the highest number. Do this for every object spawned until you run out of regular budget. Once this happens, Save your map, quit, then restart the game. Do this until you have one of every object you need for your map spawned, and their run-time maximum is set to the highest.
Also note that it is not encouraged at all to delete an object, as it will never be able to be spawned again in the map. Ever. for now, just move the object to an un-needed part of the map, so it can be used later.
There is a great map available for download below, it is a pre-glitched Foundry, which you still should not delete any objects, but it just saves you the work of spawning things. When using this map you should move all the objects to an un-needed space of the map, and cover it up, to make your map look more professional.
Pre-Glitched Foundry Map