Hi Lara, also I just noticed a couple more of those "squished down surface" pieces in there. Another way to get rid of those is to select your main object, and then on the side pane go to Select > Invert which will invert the selection and get the degenerate surface pieces selected so they can be deleted.

A click on a degenerate surface (meaning a surface that is compressed down so it has no actual surface area and looks like it is just a line or a curve) will not select it but other means such as a window select or invert selection or using the scene browser can select those.

Those are usually not things that you want to make, but you can end up with them if you do something like maybe loft between 2 identical curves or if you accidentally squish down a surface so it's all compressed.

- Michael