The beta versions of the WordStar Command Emulator didn't identify absolute positions within the text, which could of course change as you edit the file. There is an ongoing process of changing this mode of operation and current versions will remove previously placed markers. You should purchase an upgrade.
The markers however, will not cause any harm being left unused. If you do want to remove them you can do so from the Insert, Bookmark menu option. The markers all start "wsK" with the next character representing the actual marker. Select the one you want to remove and Click Delete, then Close.
The only markers that don't follow this naming convention are cursor position markers (still begin "ws") but these are deleted after use anyway.