Lets get Spring started by cleaning, ( yes I know not my favorite job either) Dissolve 2 tablespoons of Oxiclean in 2 cups warm water and work into the grout with a coarse bristled brush.  Then scrub in circular motion to loosen the grime.  For extra cleaning power, use the bleach straight or add a dash of lemon juice to water mixture. Make sure to wear gloves. Wipe clean and then spritz with a cleaner and wipe down. Finally spray with a commercial grout sealer to keep your tile sparkling. Your bathroom will thank you.