Steve Walker wrote:
Take 'em off one by one, as gently as you can, and wearing a dust mask. If
you are forced to saw, drill or break them, damp them down first with soapy
water (to prevent dust flying around).

A pair of bolt-cutters is useful. Use them to split the nuts on
the fixings, rather than trying to undo them.

nut bolt head
# \
///////////////////////|
^ # /
|
|
Cut off any long bit of bolt if necessary, then:


bolt __________ / bolt head
\ / # \
x ///////////////|
cutter __________/ \ # /
\
Cut the nut in half, on opposite flats, so it falls off the bolt,
which can then be pushed out.