The door to my shower stall will not close properly. The magnetic strips on the door and door facing will not connect.
Do I clean the magnetic strips and if so with what or do the strips need to be replaced ?

Help me out here... does the door fit the opening properly.. Is closing of the door smooth besides the magnetic strips.. If all good then seems a good cleaning is in order... if not... you could always replace the magnetic strips by special order I am sure. Answer the questions so I can better advise!

Thank you for your quick response.
No , the door do not close smoothly beside the magnetic strips.

Look at the door frame... has it shifted or loosened at the screws. Is this a regular shower or a neo-angle type of shower door..

Most likely things have shifted a bit due to time... may always need to pull hard, etc. OR if looking for smooth operation may actually need to replace the door and start from scratch.

Start with a good cleaning... study the door and its relationship to the seal... let us know from there and we will see if we can do more... may be able to shift something (but have to know what type of door... or shower).