If you don't want to waste batting, I've used old mattress pads, old bedspreads, I've RE-quilted things I had just tied before. I save all of my batting scraps and on my practice projects, I use the leftover batting and just piece it. Any small pieces, I cut into 4x4 pieces and use them for cleaning my machine.
I was told to clean the rails, bobbin area, wheels every time I use the machine. I just spritz the cotton batting bits with alcohol and wipe EVERYTHING, dust it well, make sure there are no bits of thread or lint in any of the rails or on the wheels. I do this while the machine is warming up. I just let it run, without thread, for about 5 minutes while I am cleaning. Then I oil, wind bobbins, etc until the machine is ready to go...oh, and I also do some practice stitching just to double check the tension before I start on my quilt. When I'm done with one, I can't wait to start on another!