4K remasters.

I've cleaned up some old Looney Tunes shorts and typically got the best results cleaning old film or sometimes VHS captures (removing scratches, grain, color correction).

Heavily compressed H264 video is a different story. There's a ton of information lost in the compression and trying to clean it almost always comes out looking like a bad Photoshop filter. You might get better results with 2D animation that uses a lot of flat colors and simple gradients, but anything 3D or filmed that's been heavily compressed isn't going to turn out great. I wouldn't recommend it. And to anybody that's capturing stuff from VHS or elsewhere, don't be afraid to keep the bitrate high, even if it seems like overkill. And use archive.org instead of YouTube or Dailymotion. It's kind of a shame when some lost media finally surfaces but gets put up on Dailymotion in terrible blocky 360p.

Also there's a longer Johnny Quasar clip with better audio quality: www.youtube.com/watch?v=bqLMz3rM7Jc