What to do with leftover RP

So idk where to put this, so for a second time here we go...

Anyways, we all buy RP and get around 3500 ($25 Card). We make purchases, usually on sale skins, on sale champs, and 975 maybe legendary skins. And we almost ALWAYS end up with a stupidly amount of RP at the end (mine currently at 165). And we can't do anything about it. I feel we should be able to do stuff with that leftover RP to really put our money to use. There should be a system where you could transfer RP into IP or you could purchase runes with that leftover RP, anything. Let me know what you think, thanks!