I have a Brother CS 6000, Not suppose to be oiled. At least that is per-manuel. But I clean my machine about 1 a month. I unscrew the plate, remove bobbin and bobbin case, there is usually alot of dust bunnies, that I clean out with a soft brush provided with my machine. I don't oil the bobbin casing, only the parts around it. I then unscrew the casing on top, of my machine ,clean it, not as many dust bunnies, because it's pretty well incased. I oil the moving parts. I don't use 3 in 1 oil. I use sewing machine oil, because it's a finer, lighter grade of oil. And I've had this one 2 1/2 yrs, my old brother I did the same, and I had it 10-12 yrs and never once did I have to take it to a shop. I just recentely gave my old Brother as a gift. I had a Kenmore before my Brothers. I use my machine on the avg of 5-6 days a week. So this is what I do, and it's tried and true for me.