My grandparents' house is 50 years old. Nothing has been done to them in 30 years or more. Kitchen has fir and the rest of the house has wide board pine. There are gaps in between the woods maybe not but it began to look weird.I'm planning to renovate the entire house floors.
The rooms and living room have wooden cupboards so I'd love to have an antique flooring which can match the shelves. Is there I can do to fill the gaps as a temporary relief on my own? If so please tell me the particular product and or method which would be best? There is already stain applied to the floor so whatever is used must work harmoniously with this product.
The suggestion I give it you about using flooring nailer if using the wooden floor whether solid or engineered. This will work like magic. As there are gaps as you already told you can use any sealant.
if you have rust you may want to take a look here and see if this can help with the rust? https://www.buzzfeed.com/cool-guide/salt-brands-1mp2bp21x1