The best way is to carefully remove the case completely and refit the tape and spools into the case of an old unwanted cassette. Try to avoid touching the tape with your hands.
Colin
January 2008
I can answer this question...
How do I fix a VHS tape that the case has been broken?
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix cassette recorders.