How can you stop MIL from always having her finger in her nose 90% of the time?

If you make cleaning the nose with a Q tip dipped in Vics Vaporub a routine procedure at the morning toilet, her breathing will be easier and the nostrils stay soft, therefore she may forget to pick because the nose feels clear.

If they have done it all their life's in private or not you will not stop them. Sorry that's reality. If it bothers you you will just not be able to include the one you love.

When I give her a cup of tea or something to eat, my 95-year-old dementia patient mother uses her napkin to poke around in her nose, sometimes to the point of making it bleed. Yuck, right?

I don't know how to stop this, but I CAN tell you how to make it continue for sure and that is to make a big deal of it. Sorry about that.

Good luck.

My mother rubbed a spot on her cheek until it was irritated and "grayish". We had success in giving her "Tangles" and other things that can be manipulated in her hands. HOWEVER, the most successful diversion has been "bubble wrap," the packaging material. I cut it into strips from the roll (you can buy it where packaging materials are sold), about six inches wide. She pops them one by one. Try some music playing simultaneously; it can entertain for a half hour or more. This actually seemed to have cured the habit. Now she enjoys this still, never seems to get tired of it!

How sad we have to start hiding our elderly because they gross out family and friends.

Perhaps you could feed your mother in law first and have one of your family sit with her in the living room while the others eat. It may help to explain to your family at least that she can't help doing this, which I'm guessing is the case.

You may also want to think about placing her food on her plate first, then have the others serve themselves away from the table so there won't be any serving plates at the table at all. While she may use her hands to eat her own food off her own plate, at least she won't be taking it off serving plates.

If she does the nose picking at the table, just tell her outright, 'mom, please stop picking your nose'. Or sit next to her and manually stop her without having to say anything.

The brain is a mysterious organ that controls our entire being. At some point, we may all find ourselves picking our noses in front of our relatives and friends but unable to do anything about it. This is why as caregivers, we must take into account how we would feel if we were in that position and what we would want others to do to help us.

You probably won't be able to change her diet at her age. But you may want to consider ways to prevent yourself from being a nose-picker. My guess is, her sinuses are probably out of whack (stuffy and dry at the same time). I personally have found my sinuses cleared up amazingly with a low carb, high (good) fat, moderate protein, and high fiber diet. This diet is also known at the ketogenic diet. You can google it. A lot is available on YouTube. Dr. Jeff Volek of the University of Conneticut, Dr. Stephen Phinney of UC Davis, and Dr. Eric Westman of Duke University are great sources on info.

"Picking" IS part of dementia symptoms, should she have other signs. One way to deal with it with dementia, is to give the person something to 'hold' in their hands to keep their hands busy. Something else they can 'feel' and hold, rotate, twist around. If it's not dementia, but simply a 'bad habit', I would say something simple and non angry like, " Mom, looks like you need a tissue." while you had her a Kleenex and see if that diverts her somewhat. Habits seem to get worse in the elderly...and they certainly do NOT go away! As far as the issue of her picking up food off serving plates with her hands, I would try to anticipate that and simply 'serve' her first...get her 'set up', give her a napkin...much like you would 'prepare' a child to eat at the dinner table...and see what behaviors you can divert that way. It's good for the elderly to be included, so how to keep everyone 'comfortable' is the key. Perhaps you can create a 'buffet' situation, so all serving dishes are not on the table, and each serves themselves. you could then offer to 'get it for Mom' so she 'doesn't have to get up' and thus she is not really singled out over the other guests either. You could quietly explain the change/reason to those who need to know what your plan is....which is to keep her fingers out of the serving dishes so everyone can enjoy dinner. That way, if you have guests who would think this strange, or not comfortable for them, then they will understand your rationale.

Try Joannes suggestion of giving her hands something else to do - rummaging box, stuffed animal, or stimulation mat. It is possible that she has now caused a sore inside her nose so her instinct is to touch it. Maybe a doctors visit is due.

Picking is also part of obsessive compulsive disorder (OCD). Dementia patients which OCD will pick anything they used to when no one could see them.... Dementia removed that stigma about what is appropriate in the society and your mom is just doing what comforts her.
Also her OCD can come with depression. One way to deal with it -- to redirect, take right vitamins/meds and keep her hands busy.
Watch Teepa Snow on u-Tube and learn how to recognize those problems and how to deal with that behavior.

See if clipping the hair out of her nose will stop her from picking. As we get older, more hair grows in places we least need it...ie: chin, face, knuckles, tops of hands, top lip and , very often, inside the nose. It itches, it tickles, it can drive a person crazy. EVery breath we take makes those pesky hairs move.
I had to get a tiny battery operated clipper to cut the hairs out of my nose!!