How do I tell if comics are worth anything and where would I sell them?

Just finished cleaning out my now hospitalized hoarder alcoholic brothers house and I found about 5 rubbermaid tubs full of comics. Most are not sealed in plastic and I doubt any are real old. He's now 45 and has probably been collecting since he was 16 until he began really drinking heavily about 5 years ago. Is there a guide to judging comics worth? I know nothing about comics, but I know some are valuable. Thanks