Power, audio turning on but no visuals out of TV.

My Super Nintendo is turning on but no visuals come out of the tv when I put in most cartridges. When I put in a game the Audio of the game will play and the no signal sign will turn off but nothing will show on the Tv. I was able to play one game after a few reset tries but it doesn’t seem to be a reliable fix when I switch out games. For all my games the audio will play on the Tv but nothing will come up. Any suggestions here? Maybe I just need to clean it if so how can I do that?