Steam Complimentary Remove

You can hide them by right clicking them in your library and going to set categories. If you use Ctrl+click you can do it to multiple titles at once.

Otherwise, if you actually want them removed, I think you need to contact Steam support.

ctrl+f complimentary, dunno of any other method

By complimentary if you mean "free" games and stuff then googled this might help you. Use at your own risk and you can always re-add those "free" games you wanted back.