sell and delete game
Prices haven't really changed yet, give it a few days to see if new players start buying up skins, then sell.
In general All skins will value, enjoy and buy the sticket katowice 2015 (since there are very few), with f2p many people will invest in the market ..
I'd wait to see where prices go before I sell.
I guess this is what valve intended, more players > more investment in the market, they plan that they will earn more through the market than the game price.