if replace is not working, they might not even be there.
The \ can be inserted by UiPath for display purposes, to correctly display the single quote double quote part of the string. It depends a bit on where you (re)view the string value.
But… yourExcelValue.Replace(chr(92), "") should work. chr(92) refers to the \ and avoids accidently being interpreted as an escape character in your replace expression
It is indeed an interesting one, that the replace does not work.
A final check that you can do to validate the actual data in the variable is to dump it (write line) in notepad for example.
Because somehow it is there or not, and the debug fields of uipath treat all output as JSON and thus escape stuff.
Edit: does your find and replace throw an error, or simply nothing is replaced?