Sorry, I didn't know it was different for every phone model.
I have a Sharp SH-12C. I didn't install any custom launcher or home app.
The Android version is 2.3.3.
One app is the game UNO, which after uninstalling left this grey square with the X behind. Another one came with a SIM card I used in Vietnam. It was called SIM Toolkit, I don't know what it was for. Since I'm in another country using a different SIM card now all that it left behind is the aforementioned square (although the new SIM card gave me a new SIM Toolkit).
The icons are not in the Home screen, where I could drag them to the waste bin, but in the app screen. As far as I know there is no waste bin there. Long pressing only makes them drag and droppable.