If you finger nail catches the scratch then it is too deep to use ScratchX or any other product, but you can reduce the scratch with scratchX.
If you want to take out the scratch completely you would have to do color sanding and then use a rotary buffer to take out the sanding marks. It is also possible to just buff out the scratch depeneding on how deep it is using the right product and a high speed rotary buffer.
If the scratch is pretty deep and you don't want to take it to a shop then you could use touch up paint to reduce the visibility of the scratch. If you want to use touch up paint I recomend you to use this
http://www.autovisuals.com/ and order an autosharp pen with your paint code. These pens are nice since you have more control.