On 25/05/2016 08:58, Dave Liquorice wrote:
Squirt of
silicone based furniture polish on a bit of kitchen roll wiped along
removes the cack and reduces friction almost to zero. Works on ali as
well. Hooks that fit around the track, things that run in a slot
aren't easy to clean.

We always have straight silicone spray around. Very effective. :-)

--
Rod