In article , newsb
writes

When camping, we used to squirt a line of washing up liquid around the
edge of the groundsheet - it always seemed to keep them out. It
probably wouldn't persuade them to leave your wall, but it might be a
non-lethal way of stopping them coming into the room - and if that is
where they're looking for food, they might just leave.



I think that clove oil will also work a treat at discouraging them.
--
Janet Tweedy
Dalmatian Telegraph
http://www.lancedal.demon.co.uk