Is it a drop-in bobbin or the other?
If the other, there's more you can do than just take out the bobbin case and clean. There should be a knob you can move to remove the entire bobbin race. I do that on my machine, clean everything, then run a light glaze of sewing machine oil over the bobbin race with my finger before replacing all the pieces. The only thing is that it can take awhile to figure out how to put everything back if you are not used to this procedure (but you *can* figure it out!).
Also, I usually take off the needle plate and clean that area from above.
If there is something caught in the bobbin area, doing these things can help you locate and remove the thread or whatever is jamming up the system.