I've just got an allotment, after a four year wait. Sadly, the shed that was on it burnt down last summer, leaving an area of burnt soil covered in charcoal, nails, glass and bits of half burnt chipboard. My question is, could I just pick out the nails, glass and larger bits of wood/chipboard, and dig the smaller bits in, or would that potentially contaminate the soil? I'm not too worried about the wood but wonder if the chipboard might have left the soil contaminated and unsuitable for growing veg. Anyone got any thoughts on this? Picture attached although not that easy to make out the damage.