How do I remove mud (and other substances) from my blue tshirt?

Hi, I went out friday to a club and i had my tshirt there to put over my dress for when it rained. Basically i dropped it on the floor, and this wasn't a clean club. It's known for how disgusting it is but it's the vibe that counts. Anyway, it looks like mud but it could be a number of different things on my tshirt, alcohol, piss, sick even. I washed it in the sink the next day and then soaked it with biological liquid for a night. I then stuck it in the washing machine as usual, it's significantly cleaner but there are still a number of set brownish muddy looking marks that I can't seem to remove?! :( It's a favourite tshirt so i really would appreciate some feedback! Thanks.