The message
from Dave Fawthrop contains these words:

Our Coffee Grounds & Tea bags, go in the Compost Heap along with potato
peelings etc. I wonder what the effect of caffeine is on worms.

Apparently it gives slugs the whizzes - enough to discourage them. At
least, they can be seen rocketting off into the distance with steam
emerging from underneath.

--
Skipweasel
Pay no attention to that man behind the curtain.