We will add some information here that we hope will be helpful should you want to start performing some basic clean-up of your valuable Cameras & Lenses.
Basic Leather Care: Perhaps with my 'country boy' upbringing I expect too much. I would have thought that basic leather care was something most people would have at least some idea about, but alas it does not seem to be so. I have received many dozens of camera and accessory cases that appear to have never seen the slightest sign of ever being 'cared for'. In fact, its quite rare to find any that have. These are leather, not plastic, and were living tissue once, and as such a bit of care will go a long way. I have had 2 very nice looking cases come apart in my hands while cleaning them... why? Lack of care! Every piece of leather I receive, even NOS (New Old Stock) ERC cases we own, get at least a quick dose of care. Even if it looks perfect the stitching and or leather is probably 'thirsty'. In overly humid climates they can rot and are mildew prone, in dry climates they can 'dry rot' from lack of moisture. We use some museum quality products such as "Leather Rejuvenator", "Renaissance Wax" and "British Museum Recipe" leather conditioner. The first 2 you can find on Amazon, the last one only in the UK as far as I know. Other's that are a bit cheaper and easier to find that we have used are "Saphir Creme Universelle" for the newer or virgin leather, or Lexol Cleaner and their Conditioner can be used on older cases, and sometimes Neatsfoot Oil as well. Any of these will help, so choose what fits your budget. The old ERC cases are well tanned and made of very good leather, so they hold up well, as do the leather coverings on the older Rolleiflex, but they can always benefit from a little care. I have spent hours on just one old case or camera body, removing decades of dirt, shoe polish and grime. (some not very honest eBay sellers or dealers use shoe polish in liberal amounts) A good quality beeswax shoe polish can be used for leather care also, but I hardly ever use it. Beware of very shiny old cases, they have probably been polished, and may be very ugly underneath if/when cleaned! After caring for them all are kept in my humidity controlled closet, in plastic and at less than 50RH, which is a necessity here in Phuket due to the tropical climate.
Basic Camera Care: As with the leather above, camera bodies, at least the old Rolleiflex's, can benefit from a bit of extra care on their leather coverings. I always go over every camera received with a 50-50 pure alcohol-water mix with swabs and clean every exterior crevice and then polish with clean micro-fiber cloth. The leather is treated as above. All are then kept in one of my 'dry boxes' at between 40~45 RH (Relative Humidity). It is usual to run through the shutter speeds on these old cameras at least a couple of times per year. Most of my cameras have been, or will be, CLA'd with the exception of a few "near perfect' cameras that I will not take the chance of getting nicked up during a CLA, even by a professional, it happens. These are not intended to be 'user' cameras in any case, and some may end up in a museum someday as perfect examples of the species :-)
Camera Lenses: Many of our lenses, especially if pre 1970, are sent for CLA prior to listing, or cleaned by us if only minor cleaning is needed. I try not to do much lens cleaning on my own, but when I do I follow the great Harry Fleenor method laid out in his websitehere. After cleaning, whether by me or a professional CLA, the lens caps (for Rolleiflex) are normally kept on and for the Leica lenses, most (except some odd sizes) have a UVa or SL (Sky Light) filter kept on at all times thereafter, and lens caps stored separately. Try to avoid cleaning these valuable lenses yourself as the coating can be marked (scratched!) quite easily, and as Harry says... "Gently... gently..." That said, as most of the cameras on this site, or any cameras more than 40~50 years old, chances are the lenses have been cleaned multiple times, and most agree that some cleaning marks, light scratches, even light fungus have little or no effect on the resulting photographs. Collectors pay much more for perfection, photographers, on balance, will prefer the reduced cost of 'used' lenses as they know that the picture quality does not usually suffer.