I would like to know how to make reference to this character which is displayed in the data editor as a square but is somehow read as �.

Code:
* Example generated by -dataex-. To install: ssc install dataex
clear
input str13 registro
"86057��"     
"150737�"     
"0019634�"    
"��"          
"11415�"      
"0264745�"    
"18226�0"     
"278145�"     
end
I would like to replace it with "". The code below does not work.
Code:
. replace registro = subinstr(registro,"�","",.)
(0 real changes made)