Water temperature should not exceed 30 °C (86 °F). Pretty much like cold tap water.
DO NOT wring, neither by hand, nor by machine. You could damage them.
DO NOT use the iron at all. Be careful with your printed t-shirts, they’re often a problem !
Good old ways ; wring your clothes and hang them on a rack or on a washing line. Takes more time but a lot safer for your clothes.
DO NOT dry-clean, even for a deeper wash.
DO NOT bleach. Unless you want to change your clothes’ colors