Sometimes I find words that I can't read while reviewing. Is it okay to keep the stars in place of the letters?
We use a question mark (?) as a “wild card” for a single unreadable character, and a single asterisk (*) in place of a consecutive series of two or more unreadable characters. We never use two question marks or two asterisks in a row, or a question mark and asterisk next to each other. You can also share your batch here with that specific question, and someone might be able to make it out. There are some eagle-eyed Indexers out there.
Below, from the General Indexing Guidelines (should be the last section of your Project Instructions) is a link to a more detailed article on this and related situations:
GENERAL INDEXING GUIDELINES (GIG)
Here is the list of General Indexing Guideline (GIG). They should be the last section of most projects these days. Some projects still have similar information under the heading "Additional Information." You can see that the GIG is a treasure trove of useful general information. It applies when the Project Instructions (all parts - examples, Field Helps, etc.) don't advise to the contrary. I think that the links are live so that you can explore them. The answers to many questions posed here are in the GIG.
Thank you for answering, and thank you for answering all of my questions.
The indexing guidelines also helped.