First of all I have no problem when my answer is not accepted, I can always be wrong, but there are cases when I must think I really answered correctly and noone else answered. I put in lot of details, received upvotes, but still the answer is not accepted. In these cases is there any polite way to remember the question owner to respond (either to accept or ask further)
There are two options:
If you go with the comment, make sure it is polite. If the user is not a brand new user, the comment is most likely useless so you should not post it.
Remember that while your answer might be technically correct, well detailed, compliant with best practices, etc. it still might not be the answer the poster is looking for.
You can't force anyone to accept your answer, that's optional and up to the asker to decide.