[Q] How to go unroot after rooted using framaroot

Hello all, new member here.

Ok. First of all, I'm on stock ICS, rooted using framaroot http://forum.xda-developers.com/show....php?t=2130276
Installed busybox and installed the applet using smart install.
Now I want sell the phone and I want my phone go back to "completely new unit".

In busybox it has option to uninstall the applets.. Warning popup came out like WHOA! bla3x... I don't have gut to continue so cancelled it..
In framaroot it has unroot option - this worked for me to unroot

My question is:-
should I uninstall the busybox applet?
Do I have to flash ICS stock rom using odin?

Anyone have same problem like mine? What u did?

please help :(