you have pm mate
Free I don't think so!!!Bottle will need replacing, but AP should do this very cheaply or even free.
Also people open them and either let them go or open them when they don't have enough gas left, so they are often submerged with no pressure keeping the water out.The reason these bottles corrode is because people leave them rolled up and wet, let them dry out, then roll them back up and they last a life time.
Did you borrow it off a certain Mr Payne? If so what sprayed you may not be what you think it Was ....mg:I once opened one in the NDC car park and got sprayed with water saturated in aluminium rust. It was like milk.