Preview: Removing highlights from a PDF after resaving

If you saved the PDF from the File menu, then you didn't flatten the PDF and the Highlight annotations should be removable. Open the PDF, and then press cmd+i to open the Inspector. Then click the Annotations Inspector as shown here:

If the PDF was not flattened, you should see a list of Highlight annotations. You can select one or non-contiguous Highlights by using the ⌘-key, then press the back space key to delete the selections from that Annotation Inspector listing, They will immediately disappear on the PDF.

I don't com my notification

I have been trying for hours to figure out how to flatten my document using preview. I’ve tried saving and exporting and printing and all that- how did you manage to flatten your document?