Encoding error on save

I'm getting this error when trying to save an IFS CLLE:

---
Save Problems
Save could not be completed. Try File > Save As... if the problem persists.

Reason:
Some characters cannot be mapped using "Cp1252" character encoding for file
{IFS path here}. Either change the encoding or remove the characters which
are not supported by the "Cp1252" character encoding.

Details:
Input length = 1
---

Is there a good way to find the characters it doesn't like? Just
eyeball-ing it, I don't see anything that looks bogus.

Thanks