Hello,
you could you try this for a single character
${manufacturerName!}_${manufacturerSKU?replace("#","")}
If you want to remove multiple special characters you will probably have to use regex:
${manufacturerName!}_${manufacturerSKU?replace("[\\.\\+\\\\#=\\?]","","r")}
This will remove the following characters: \ . + # ? =
Sadly I'm not that proficient in regex so I don't know if there is a better way to resolve the issue.
Alternatively you can use the built in Synesty Function to replace each undesired character with nothing:
Kind Regards,
Stefan