Okay, so I was quilting on my machine. It said it needed oil, and I wanted to finish the quilting I was doing (all I had left was the top border). So I kept going and the thread broke. I grumbled and rethreaded it, and did the thing where I bring the bobbin thread to the top. Except it wasn't working right, I would pull it up and get like 4 strings of top thread. So I rethreaded again, same problem. I gave in and and took my quilt off and oiled the machine.

After I oiled, I always run through white thread on white fabric to make sure it doesn't turn oil color. I was doing that, and the bottom thread came out fine. But the top thread was grey. I figured I had either put grey thread in (nope, white) or was crazy (pretty sure that's not true). I tried a new piece, and sure enough, the top white thread comes out with a noticeable grey color. I've never seen that happen with the TOP thread. My machine's due for its annual checkup, I was just putting it off since the shop that does it closed so I have to take it about an hour away.

Any idea on what is going on with my machine??? (Bernina 430 if that's relevant)

Is the thread binding on some sort of black rubber washer? If you run it on scraps, does it get white again?

Could it be the oil. Does it come in contact with any part you oiled. I have never had that happen before.

Not sure exactly what you mean. After I posted this, I took a break from the machine. When I came back it was less grey (and I did have the boyfriend verify that there is a color difference and I'm not just crazy). So it's not as bad, but it's still not fully white

I oiled the bobbin area. I used the same amount I always do. Usually I get a little on the bobbin thread as it comes out immediately after being oiled, which is why I do the test whites. I'm not sure exactly how the top thread goes into the bobbin area, but I guess it would make sense that it could come into some contact with residual oil...

I had this happen to me too. I sewed on scrap fabric until the thread was clean again. I think dust in the machine dissolves in the oil and that stains the thread.

It is oil. You should use scrap fabric and stitch on it until it goes back to normal. You will have to do this again after it sits a time or two depending on how much oil you used.

Thank you!! :)