I usually wash my gloves with bar soap then rinse while I'm wearing them... just like washing your hands. Then let air dry. I'd toss 'em in the laundry but I don't like any more velcro than is necessary touching my other clothes (even if you do up the velcro strap there's usually a bit sticking out).

Helmet... after maybe every 20th ride I take it with me into my post-ride shower. Then let drip dry on a towel.