"Wallaby Walker" writes:
Apparently there is a poison product that "mummifies" the pests so that they
don't "jelly away through you ceiling" yuk!!

Why not glue a rattrap into the middle of a large tray or sheet of
cardboard, so you can drag it to the manhole and remove it from your
ceiling? One disadvantage of a rattrap is that once one rat has been
caught, the others will usually be very wary of going anywhere near
the trap for a few weeks. Whereas with baits, once one starts to eat
it, others join in, and they all succumb only after a few days. Most
of the time, the baited rats do not die in the walls or ceiling; for
some reason they seem to seek sunlight, and you'll find them dead or
dying outside on the concrete path or on the lawn.

There is the "rat glue" product. You could put it onto a metal tray
or stout wood board, but it doesn't kill the rat, just holds it fast.
So you have to put up with its squeals and go and finish off the
captive rat (unless it chews its own leg off to make an escape, or
dies of shock).
--
John Savage (for email, replace "ks" with "k" and delete "n")