These are Canada 1890's vintage stamps from the Small Queen issue (as apposed to the earlier Large Queens which were physically larger in size. Also known as Small Heads and Large Heads in Great Britain because I think that is what their catalogue calls them.
They are Scott stamp catalogue (used in North America) #37 OR #41 and possibly varieties of these numbers depending on the exact colour and paper and perforations (holes around the edges)
I am not sure of your stamping knowledge so am talking here as if you knew nothing.
I am no expert on these and there are some web sites out there (including this one) to help a person figure these out.
Do you have a perforation (perf) gauge? You need to measure the perfs and let us know what they are across the top and then down a side. You can also measure them by seeing how many holes and a fraction thereof are within 2 centimetres on a ruler. You should end up with numbers like 12 x 12.2 or something, the first number being across the top and the second being down a side.
You can get one at a stamp store or on
ebay.
Colour wise, these Queens are a hard bunch for most people to peg dowwn to exact colours.
Your first one has an orangey tinge to it, the second stamp is faded by sunlight a bit but the third is a really nice solid colour, and with a nice partial dated New Brunswick cancel from March 1, 1893.
If any of these is an Orange Red shade and if the perfs also measure correctly, it could be a more rare one and slightly worth more.
However, the bad news, the first stamp has a bottom right corner cut off and this devalues it considerably, nice colour though.
The second is not centered well, the whole design within the whole outside of the stamp I mean. This drops its value also a bit.
The third is centered better and the design doesn't cut into the perfs but still not perfect. Also the top left corner is kind of banged up and that doesn't look good on the valuing either.
I just thought that Bee See may be along here and could perf your stamps electronically for you but I don't want to volunteer his services.
They are all good colour and do not seem at all 'oxidized' (wrong chemical word but everyone uses it.) or looks brownish due to chemical reaction with the atmosphere. They have been stored well.