In our instance we have enabled server side forwarding from Analytics to AAM but there are lot of signals which we are not planning to use to create traits, so is there a way we can delete them to limit our activity usage?
Signals that were already sent to AAM cannot be deleted. However, you can prevent Analytics data collection hits to be forwarded to AAM (and hence excluded from usage) by using the contextData attribute: s.contextData['cm.ssf']='1'