Do Barcode Masks Have to Remove Certain Characters?

You don't have to modify your barcodes at all if you don't want to, the masks can be set up to just read and interpret the barcodes as is. Doing this will mean there is a lesser chance of something going wrong and them being scanned incorrectly, but it will mean they are harder to read in management if you have larger barcode such as those from an SLS.