Question: use nail polish to keep a button on
Options:
If your button is starting to unravel, paint some nail polish on the thread and button to keep it on until you can get it pulled off
If your button is starting to unravel, paint some nail polish on the thread and button to keep it on until you can get it sewn back on
Answer: If your button is starting to unravel, paint some nail polish on the thread and button to keep it on until you can get it sewn back on