>The problem is that I do not know what they all may be. There are many of them used in FPD26 for line drawing, etc and special characters and they are all entered as =CHR(whatever#)...
>

Then the form hack should work just fine after backing it up somewhere for good measure, e.g.
[evaluated expressions in captions are stored like this e.g. caption=" =Chr(195)" is stored Caption = (CHR(195))
here's an updated version to handle both =CHR(x) and ="Some string"

#Define CR Chr(13)
** set those with CHR(x) in label expression to empty caption
Update theForm.scx ;
  set Properties=StrTran(properties, ;
	  "Caption = ("+StrExtract(properties, "Caption = (",CR), ;
	  [Caption = ""]) ;
  where baseclass="label" ;
  and "CHR(" $ Upper(StrExtract(properties, "Caption = (",CR)) 

** set those with ="Some string" to just "Some string"
Update theForm.scx ;
  set Properties=StrTran(properties, ;
	  "Caption = ("+StrExtract(properties, "Caption = (",")"+CR)+")"+CR, ;
	  [Caption = ]+StrExtract(properties, "Caption = (",")"+CR)+CR) ;
  where baseclass="label" ;
  and "Caption = (" $ properties

USE in theForm
Modify Form theForm nowait