How to Install Custom Jars in Minecraft
Due to the 1.6 update, installing a custom jar file in Minecraft has changed. This article will tell you how to install the hacked client, 'Weepcraft.' This can be done with any client as long as you have the jar. This article assumes you have the latest version of Minecraft with a premium account.
You may call this something else. If you do, you must call the jar and the json file that name too.
6.* json file (\AppData\Roaming\.minecraft\versions\1.6*) and paste in the folder called Weepcraft.
json file using Notepad or Notepad++
Save and close everything.
On the release version drop-down box select Release Weepcraft.
Select your profile in the bottom left corner and hit Play.