I use Tile Lab Gloss sealer. Makes the grout so much nicer and finished. They guy at Home Depot said I didn't have to wipe it from the tile, so I don't. It makes the plastic beads shiny again after the grout dulls them.

Yup, what Slow said, tile/grout sealer. I find the better quality you buy, the shinier. I buy mine at a tile store, more exspensive than say Home Depot, but I like the finished look, and most of my pcs are for outside so I use outdoor grout and outdoor sealer...which are not sold in hardware stores.