There are various types of wood oils which bring out the natural beauty of the wood and nourish it/stop it from drying out. You just brush it or roll it on using a roller designed for oil. A brush would be fine for small pieces. Europeans tend to go for linseed based oils, but I'd choose a hardwax oil. The wooden floors in our house are hardwaxed using this:
Fiddes Hardwax Oil. It's made in England but available in Poland. You can get it clear or tinted in various shades.
There are various types of wood oils which bring out the natural beauty of the wood and nourish it/stop it from drying out
Years ago I found a nice old coffee table in a skip. Solid wood but very damaged surface. I just put olive oil on a sponge, dabbed it very thoroughly all over and it looked great.
Does it protect the wood from minor scratches and gouges?
Scratches, yes to some extent, gouges no. It doesn't seal the wood like varnish. The purpose of hard wax oil is to nourish the wood and keep it looking lustrous. It works into the wood as opposed to sitting on the surface. You polish it as often as you like with a nice natural wax polish and buff it to a high shine if you want to but there will be a certain amount of sheen even without that. Wooden floors look fine even with some wear and tear. I wouldn't see minor scratches as damage.
Black permanent marker pen works ok as a concealer on dark wood. There are special pens you can buy in three shades of brown though I've found that the colour isn't especially fast with those and black works better.
Sorry, no. I do the cleaning with a sponge. You can`t see one in the pic. It is sth different. Hint: What is sb`s had holding over the water?? And what is lurking in the water below???: