Yes you are totally correct in that how you handle your discs is paramount to performance.
I cannot say that I agree with your 'spit and a hanky' advice though. Saliva is a mixed soup of enzymes and I certainly would not want them on my Laserdiscs! I have, for delicate cleaning jobs including audio and video tape heads, camera lenses...and now my Laserdiscs (along with a soft cotton, non-shedding cloth) used Isopropyl Alcohol - sometimes called Isopropanol. It cleans well and will dry without leaving a greasy residue. I susally use two soft hankies, one to apply and one to wipe off. I dampen a section of the on-hanky and, working from the centre outwards, wipe outwards to the disc's edge. If you imagine the disc as a clock-face, I usually do it in '5minute' segements. Then I switch hankies and do the same middle-to-edge movement and remove the last of the by now drying alcohol.
I do not so this for every disc I buy mind you, only ones that are smothered in fingerprints. Thankfully they are actually few and far between, and it is clear that most of the folks that i have bought from understood what "carefully" actually means.
Once you LD's is back in its lined paper sleeve, you are good to go. General good care and delicate attention should do the trick from that point on.
You can only usualy get Isoprop Alc from a pharmacy and, you will have to say that you are using it to clean optical media, but it should not be a problem to buy. Beneficially, following these tips, a bottle will last for years, as long as you remember to put the top back on properly...it evapourates very quickly!