Yep Noel, thats just the way my rags look when I do that, and everybody else's too. ;) Sounds like you're doing the right thing.
And I think you are asking if veggie oil is mineral oil, if so, no veggie oil is not mineral oil, two totally different animals. If you are not going to "use" a piece,its just fine to put mineral oil on it to keep it looking slick and and keep it from rusting. A piece you use pretty often, put some other kind of oil on, like olive oil or veggie oil. I don't like veggie oil myself, it gets stick after awhile and is a real bear to get off, but if you use it every day or so, no problem, olive oil won't do that. If you decide to put the piece into service that you put mineral oil on, wash it off good with dawn and hot water, it'll cut if off no problem, season it up and you are good to go. If I don't use a piece, I don't season it because I don't need it seasoned if I don't use it, and if I want to season I always can. Thats the way I do it anyway.