Big hands, or hands that can't squeeze down well on a small object, like arthritic ones.
There's a theory that bigger grips slow down the release of the hands, so they might increase a tendency to fade (or decrease a tendency to draw) but I doubt that this is a really important effect for the average hacker.
While white spirits can be used to remove old grip tape and residue from golf clubs, it is not recommended to use them for installing new golf grips. Using a gripping solvent specifically designed for golf grips will provide better adhesion and help extend the life of the grips.
Lamkin sells golf grips, including specialty golf grips, putter grips, cleaning wipes, and other types of grips. They also offer training on how to properly use the grip.
There are many places online that have information on good or even great golf club grips. One of the best sites with information on these club grips is Google Reviews.
Unfortunately not, you can not use these grips at any level of official competition. The grips are against the rules because they have fixed hand positions.
This seems to be the same idea, and they say they are conforming, would be interesting to hit. http://www.feelwedges.com/Grips_s/60.htm
Yes.
humidity
In the earlier days, leather was the material selected for golf club grips. They are still available today, but quite rare and expensive compared to other grips.
use sand paper on them
Golf Pride VDR Red
You shouldn't really use any house hold cleaner on golf club grips as it will destroy them, enjoy the mild ones. A clean towel and clean water is absolutely perfect. You can buy some specialist golf grip cleaners over the internet or in golf shops.
The best thing to do is clean the grips. This can be done easily, get some liquid soap and and nail brush, clean the grips, wash off and dry thoroughly with a towel. If your grips are shiny you should probably replace them, grips should be replaced every 40-50 rounds.