I am cleaning, adjusting and oiling the 301 that I bought about 2 months ago. There are 3 oil spots on the top of the machine near the hand wheel. When I take the top off I see that these 3 holes are plugged. Are these wicks in the hole that I should leave alone? Or are this holes filled with years of accumulated lint and dust that needs to be cleaned out? I have looked in both the machine manual and the adjusters manual but I have found an answer.