How to clean a sewing machine
How often should you clean your machine? That depends on how often and how long you use it, and what sort of projects you sew. If you sew lots of woolly fabrics, towelling, fleece or minky, felt or flannel, then you’ll need to do if more often than if you sew a quick cotton skirt once a month. If you live in a very damp, rainy, humid or salty area, you may need to take care of it a little more often and be prepared to add a little more oil.
Here you have a video tutorial on how to clean a sewing machine that might be helpful.