I'm not seeing what you're referring to, but this thread is over 10 years old, so all bets are off. ;)
 
I don't know about copying from Sonar and pasting into Audition, but you should be able to bounce a clip in Sonar, then import it into Audition.

You can add any wave editor to the tools menu in Sonar. You then simply highlight the track and go to the tools menu and select the wave editor. The track will open in the editor. You make your changes,, save the file in the editor and when you return focus to Sonar it will ask you if you wish to save the changes made to the track. 
 
There is now a utility that will add the wave editor to the tools. 
http://www.cakewalk.com/Support/kb/reader.aspx/2007013099
 
 
The other option is simply open your wave editor, browse to the cakewalk audio folder containing the track and open  edit and save. Always make a backup copy before proceeding. 
 
http://forum.cakewalk.com/Tools-Edit-Utility-m2671771.aspx
 
If you have older versions of Sonar I think you follow these instuctions
https://www.cakewalk.com/Support/Knowledge-Base/2007013099/Adding-third-party-audio-editing-software-to-SONARs-Utilities-menu
 
 

If you have a polyphonic version of Melodyne, try creating a region effect and locating / deleting the offending 'pop' or 'click'. Hopefully, it will be displayed as an individual 'blob'.
 
I can't guarantee that it will work in every situation, but I've removed several unwanted noises this way :-)

For me, the best software for this task is iZotope RX5!!

Cactus Music
You can add any wave editor to the tools menu in Sonar. You then simply highlight the track and go to the tools menu and select the wave editor. The track will open in the editor. You make your changes,, save the file in the editor and when you return focus to Sonar it will ask you if you wish to save the changes made to the track. 
 
There is now a utility that will add the wave editor to the tools. 
http://www.cakewalk.com/Support/kb/reader.aspx/2007013099

Good stuff. More info here:
http://forum.cakewalk.com/Question-about-editing-in-an-external-wave-editor-m3384952.aspx