I've tried a few different approach to remove a layer from the TOC, but none so far works.
The ultimate goal is to add the layer to a group, then remove it from the TOC
mxd = arcpy.mapping.MapDocument("CURRENT")
df = arcpy.mapping.ListDataFrames(mxd)
tgl=arcpy.mapping.ListLayers(mxd, "Group", df)
lyr = arcpy.mapping.Layer(OutPutLayer)
Then I have another question, even if I remove them after in ArcGIS, they are still available in my script parameters...