I've seen double base recommended as being helpful fir PmR SKIN CARE. Can anyone explain how that might be more helpful than ordinary moisturizers?
For one thing a lot of patients can get it prescribed!
Ordinary moisturisers have all sorts of stuff in them - Doublebase is a plain emollient cream with a minimum of ingredients and no perfumes. It is commonly prescribed for patients with eczema - has a proven track record for improving skin conditions.
Consider looking at hand made creams and lotions - recipes and ingredients have to be assessed and approved by cosmetic chemists and there are also EU regs (for UK makers). A number of “artisan” makers will make fragrance free or with carefully selected essential oils.
Follow the instructions, you put it on BEFORE you shower or bathe, this stops you from stripping your skin of all its natural oils. Once you are dry you put it on again.
That is why is it better.
I wonder if I would be sealing in dirt then rather than gently washing my skin with an emollient gentile soap.
We really don’t get dirty nowadays unless we have certain sorts of jobs. Any soap - anything that foams - strips the natural oils from your skin and dries it out. The idea with the emollients is to reduce that effect. I don’t use one - but I also never use soap except to wash my hair, every 2 weeks.
We are sold a lot of stuff for “hygiene” that we absolutely don’t need. To put money in other people’s pockets. Ditch the soap and use water and within a few weeks your natural skin flora takes over and you won’t smell. I haven;t used soap or deodorant for some 14 years - and I promise, I don’t smell! I’ve checked 
I only use the double base when I shower and that is no more than twice a week and wash my hair weekly with baby shampoo. Keep Dove soap for handwashing -never that stuff that contains plastic - those little bottles that you put your fingers on and press, forgetting that everyone puts their fingers on it before you.
And Yes, I don’t smell and I know you don’t smell because I have stood before you often.