Good grief! Disposal of them is a headache in the construction industry. In fact, we must have 50 or 60 pallets at the moment awaiting collection. Many construction sites are only too happy to give them away (at least the non-returnable ones, and there are a lot of those) because it is very costly to break them up and skip them. We are obviously no longer allowed to burn them, although I still see a lot of small builders doing just that. Next time you go past an active site why not just stop and ask?