Lucene Searches for $

good evening. I have been googling to no avail, but I have a TargetUserName field that contains the name of an active directory account. when a computer name comes through, it has a $ on the end of it. I am trying to filter those out, but everything I try, I cannot search on the Dollar Sign ($) I have even tried to add a tag in the logstash filter, but I am not able to search or filter on the $. Any help?