It's a good idea to be comfortable with removing the needle plate and cleaning the lint out. I tell my customers to clean drop-ins every 4 or 5 hours of actual sewing time. And oscillators (clean and oil), every 2 or 3 hours of actual sewing time. I can't tell if your Janome is an oscillating hook or a drop in. Oil goes on the race for oscillators, and under the plastic bobbin case for drop-in bobbin machines.
Here's a link with pictures:
http://shesasewingmachinemechanic.bl...-feed-dog.html