Use A for cleaning, and even in some cases where you need some lubrication but where it's NOT needing a specifrc lubericant product.
I use A to clean the faders on my TASCAM 3500 console, which is what Caig Labs recommended and TASCAM confirmed (and not the "Fader Lube", which one might think should be used on all faders.....though I use their DL100 product, which is pure 100% DeOxit solution, and no solvent.)
Some faders need more specific "lube", as they tend to come packed with a lubricant....so then B could be your option. It's really all about the type of contact material in the fader. Not sure what you would use specifically for the 388 faders....but all the other contacts should be cleaned with A.
C is the same as A....5% DeOxit cleaning solution with 95% solvent.
As I mentioned, they have the DL100 and the D5...both are the same DeOxit cleaner, but one has 95% solvent. The 5% is good when you are dealing with a serious gunk build up situation, as the solvent helps flush away the gunk.
What I found was that with the 5%, I often didn't get the best results, and ended up with a lot of excess solution, especially with those spray dispensers. They tend to deliver way more than needed. They may be good for pots where you need to shot the cleaner into it....but I decided to get some injection needles, and use the DL100. I can place just a single drop where I want it, and it's great for tight places and pots with just a small access hole.
For more easier access struff....I just use a Q-tip or a piece of cotton cloth and go that route.
In any case...with D5 or DL100...you want to use as little as possible and only end up with a thin film on the contacts...not a puddle of DeOxit.
Best way is to apply some DeOxit, clean the contact, and then do a light wipe with a dry Q-tip or cloth....that will leave just the right amount on there....thoguh of course....not always the easiest thing to do when you are cleaning small, hard to get at parts....in which case the spray has some merit as it will shoot the cleaner in there for you....but it always over-sprays, which is why prefer just a bottle of cleaner, and then apply with injection needles (same ones they sell on eBay for filling inkjet cartridges) or Q-tip or cloth.
D is the Caig Gold preservative meant for gold contacts and other precious metals....but I often use it on any contact after I've cleaned & dried with the DeOxit solution. The Gold product will help keep the contacts from premature oxidation.
I especially like to use it on hard to reach stuff that I don't want to have to clean again too soon.
With all products...don't saturate to try and make it "clean better", and don't leave any obvious amount laying there all over everything....always dry up the excess, especially on plastic parts. It's safe for "most" plastics...but you still don't want to leave liquid just laying there.
