I have an old garden shed 40 years old and it's lined with 3mm thick hard asbestos [I think anyway]. The lining is not flakey and is like a solid sheet grey in colour. My question is - is this bad stuff or not. It does not break very easy. How best do I get rid of it? and what is the estimated cost for removal. The Shed size is 4m longx 2m wide and 3m high. It used to be a kitchen in the old days but was recycled as a garden shed 40 years ago.