Here's a free class at Craftsy:
http://www.craftsy.com/class/Sewing-Machine-911/77
I haven't viewed it yet but plan to. I have taken the "Machine quilting big projects on a small machine" and it is excellent. Plus you can view it as often as you want.
I use a little stubby screw driver and take the plates off and use water color paint brushes to get down really deep inside. You can get a package of these at Wal-Mart or a dollar store. I think I got 10 for about $1. You don't feel bad about throwing them away when they get yucky.