1. Please download the Cleanmom utility from the Microsoft Download Center.
http://www.microsoft.com/downloads/en/details.aspx?familyid=14FF7073-C71B-4AD0-805A-A8E458D2C9E0&displaylang=en

2.unzip OpsMgrCleanup.zip

3. Based on the architecture of the machine you will have to use either CleanMom.exe or CleanMom64.exe respectively.
The command should look like this:

CleanMom.exe /CleanAgents