Hi Ammo,

I use Browning Gun Oil to lubricate and clean all my metal guns. Any steel models or components are given a generous coating of it before storage.
3 in 1 oil seems ok to lubricate metal parts too but not too much as it gets really filthy if there's too much of it on the gun during firing.
I've used the Browning oil as a cleaning sollution on abs and HW models too but wipe away the excess off the plastic before storage. It's good for getting that brown residue left behind by cap smoke.

Abbey Silicone Oil seems to be ok for lubricating abs and HW. I've been trying the aerosol spray, it seems ok.
I know of a much thicker Silicone oil applied as drops from a small plastic bottle which might be better on plastic slides for example but I haven't seen any for sale in the usual Airsoft outlets lately.

Here's a bit more reading for you http://mp40modelguns.forumotion.net/modelgun-cleaning-guides-f11/wd40-or-silicone-oil-t116.htm

Thank you Cerwyn, I'll go have a read now.

I took everything said here to account and this morning I oiled my guns using Abbey Silicone Oil, which I have for using on my airsoft guns. It was the Browning I was having problems with yesterday after putting it all together. There was jamming and the slide wasn't locking the hammer back after each shot or the spent cartridge wasn't ejecting properly. However, firstly, after reading this thread I ordered a sonic cleaner (£32 from ebay and can't wait till it gets here, lol) and after oiling the Browning this morning I tried it out in the evening (after cleaning by hand and oiling all the cartridges too) and it shoots PERFECTLY!

So, I'd like to say thank you to everyones posts here since they all helped very much. Oiling the gun (in particular all the parts/components which rub together) helped immensely and the cleaning of the cartridges has made a very big difference too. I'm now going to see about trying to polish up the cartridges to make them look a little better, especially my 45ACP ones, they look very worn out and used.

That's great news Ammo, amazing what a difference a little oil can make isn't it

An Ultra Sonic cleaner is a really good bit of kit. I've had mine about 4 years and it's been worth its weight in gold.
Hot water and washing up liquid is usually all that's needed but for dirtier components like Detonator Chambers or short barrels e.g. the hot water, bicarb of soda, white vinegar works really well. Mine runs in 3 minute bursts, I'll give the contents half a dozen or so bursts changing the water as required.

Polishing can be a real chore. Small quantities aren't too bad, Brasso, rags, wire wool, little brushes (mascara brushes are great )do the job but as I've now amassed several hundred cartridges, and fire them 100 or so at a time, polishing by hand is just not an option.
The answer is a Lyman Tumbler Polisher. It cost me £70, but I can put 200 dismantled cartridges in it, switch on and leave it for 2 or 3 hours.
Results are spectacular, every part is clean, gleaming, no damage to 0-rings, the piston/firing pins are spotless every time. Inside the cartridge bore is clean, smooth, just what's needed for reliable firing.

You may have read this already, but just in case http://mp40modelguns.forumotion.net/modelgun-cleaning-guides-f11/cleaning-preparing-fired-cartridges-a-beginner-s-guide-t40.htm
shows the polisher and its results.

Another advantage with it is that any minor marks or burrs on cartridge rims are smoothed over by the polisher.