Fitz wrote:

I've found one passing reference on this group in an old message
suggesting that stone crushing is not a DIY task. Short of starting my
own chain gang and smashing the lot with a trusty old sledgehammer I'm
a bit stuck.

If the old stuff was manky and you are fairly fit it won't take you
more than 2 or 3 days. How overweight are you and do you prefer the
relatively unhygienic provinces of a gym to work out in?

Once you build up the stamina in your arm muscles and callouses on your
hands, using a sledge is just a matter of breathing and rhythm along
with keeping your body temperature down.

Getting through the wall might take a week or so though, if you are not
fit for manual labour. Buy a thick slab of knotty wood to pound it on.