If it was me, I'd probably just exclude all the pieces I thought were bad no matter of subject/media first, then single out the best works and imagine the ones that you are dubious about being next to them and see if they bring down how you look at the best works for example
I dunno if that's illustrated well by showing amateurs against highly acclaimed artist, but you get my drift i hope
in fact instead of making the van gogh look bad, it just makes the amatuers look even more pedestrian