ooh, are they really made from aluminium? I see loads all over the place - might make an effort to scoop them up if they are...The blue cylinders are probably medical nitrous oxide - some questions at the mo in Parliament about making posession illegal! Coincidentally I pulled in at a layby today (the death of the Public Convenience has put bushes at a premium*), found a couple of dozen empty N2O disposables (size of the disposable CO2/Ar welding bottles) dumped in the bushes - recovered, will make good small foundry crucibles for ally, and a good source of sturdy pipe! You'd think they would have weighed them in, surely?
Dave H. (the other one)
* Old Man's Bladder, a delicate yellow flower that blossoms every 40 minutes...