Hi and welcome!
well, peanuts...
technically, peanuts are not good:1) very often raw peanuts (that aren't really nuts, but legumes) have invisible mold that is harmful to squirrels; 2) besides mold, peanuts contain certain toxins that cause liver damage (not only in animals, but humans, too).
So, to feed or not to feed?...
... some people think that it's ok for wild squirrels because these peanuts do not constitute the foundation of the wild squirrel 'food pyramid', it is their dessert/snack kind of thing;
...however, during the times of scarcity (e.g., winter, early spring) wild squirrels may rely more heavily on feeders/food from people, so it might be more than just 'dessert' for them.
...some people refrain from giving them peanuts altogether and use other foods; others do give them, but sparingly, combining with other things.
If you do decide to give them peanuts,
choose roasted. Roasting supposedly
(I am saying "supposedly" because it depends on the temp. of the roasting process) destroys mold, as well as some of the liver-damaging toxins. However, if roasting can destroy mold, it cannot completely destroy those toxins (that's why even for human consumption they are suggested in moderation). So, if it is peanuts - let them be roasted.
But it doesn't have to be peanuts only. Although, wild squirrels can be more picky about the food than the rehabs, they can still eat some variety: apples (cut in slices), avocados (
no skins, no pits - very toxic to squirrels), grapes etc. You could experiment and see what your wilds will 'agree' to eat. During winter/early spring they are not as picky. You can check out The Nutrition section and see what's good to give to them.
Some people become very creative with what they give their wild squirrels.
Just it's better either to limit or to eliminate corn and sunflower seeds.
Don't know where in Canada you are, but if you are in GTA, look for jonvince food stores - they often have a variety of nuts on sale, both shelled and in-shell.
I am sure other people will share their experience here pretty soon.
Hope, this helps a bit.