I have some basic Brothers with the hard plastic - but the part on the left side is attached with one screw and I take that off periodically and use a qtip to take out any fuzz - usually not much and I put a drop of oil on the needle bar and the moving parts that I can see. Also a drop in the bobbin case which is drop in - but very minimal. I don't see how this will hurt anything and so far the machines are still working fine. I wouldn't take a machine that cost $100 in for service when things are doing just fine so far. One of the machines is about 15 years old.