PeterC wrote:

Out of interest, is there a thin spray lube that's OK for switches, locks
etc?

PTFE dry-film lubricating spray.

Contains tiny balls of PTFE (Teflon) suspended in volatile solvents. The
solvents evaporate leaving the PTFE as a dry-film lubricant.

Apart from generally being bad, WD40 has a tendency to get onto the key
and then stain your hands/clothes, so it's a bad idea for this reason alone.

Graphite powder is good, but puffing into the lock tends to over-egg the
pudding somewhat and then that gets everywhere (your hands, your face,
up your nose, etc).

Best to use PTFE dry-film or get a soft pencil and rub it over the key,
then use the key to transfer the small amount of pencil lead to the lock.


Cheapest dry-film lubricant is from Toolstation @ £2.58:

http://preview.tinyurl.com/ygosmvm

The locksmith trade uses GT85:

http://www.gt85.co.uk/products.htm which you can buy from Amazon,
Halfords, your local cycling shop, etc. £3.50-£4.50

Screwfix sells this product:

http://www.screwfix.com/prods/80487 @ £2.83 which, judging by its MSDS
should be OK as well.

HTH