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It appears AppZapper is being supported again. Version 2.0.1 is the current version. Apparently it was rewritten from the ground up for Snow Leopard.

vx3alt
 
While I will always use EasyFind for my app. removing needs, I'm wondering if anyone has ever used the new AppTrasher? It seems to have more thorough finding capabilities that all those mentioned above. It's "expert mode" and ability to find invisible files sound nice.
 
As a previous poster mentioned, AppZapper was recently updated for Snow Leopard. People who have stated that it is no longer being supported should actually check their web site before making such statements.

AppZapper also has a "MyApps" feature. See it at their website: http://www.appzapper.com/#3
 
I've been using appzapper for a couple years now (both 1 and latest/rebuilt 2 version) and it works good on most apps EXCEPT Adobe applications.
They scatter files related to the application around and AppZapper missed one small but important file with the word 'akamai' in it.
This little file slowed down my computer and caused launchd problems that I didn't know about until on the phone with another application's support guy.
What I learned is this:
1-If an app comes with an uninstaller then remove the app with the uninstaller
2-if your computer is running slow and it's pretty much new (my case) check the console for 'akamai', ESPECIALLY if you've recently 'removed' an Adobe app.
3-appzapper (the latest version) doesn't catch every necessary file.
4-gonna try AppCleaner now.
 
None of these apps are entirely effective in removing all components of an app.
I just tested a few of these, using Skype.app as the file to be deleted.

AppZapper found 4 items
AppCleaner found 6 items
AppDelete found 9 items
EasyFind found 16 items
Finder found 17 items
Have you ever tried AppTrap?
I just tried it. What a pain! First, it leaves behind cache folders and other files, like the others, so it's not very thorough. Also, it doesn't list the files and locations first, so you can choose what to delete. It just moves the files it finds to the Trash. On Leopard, there's no way to know where the files came from, so if you change your mind, you can't easily put them back where they came from.

The only effective method for complete app removal is manual deletion:

Best way to FULLY DELETE a program
 
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