Did you mean trash, as in what you put out on the street (garbage)?
If so, my dream dictionary says that when you dream about throwing it away, it suggests that you're getting rid of bad habits or characteristics or traits (growing older and wiser). If you piles of it, it is a warning of a scandal that you can change by changing your attitude for a bad situation. If it involves someone else's trash, it foretells of trying to help another person out of trouble they've caused for themselves, or their reputation.
If so, my dream dictionary says that when you dream about throwing it away, it suggests that you're getting rid of bad habits or characteristics or traits (growing older and wiser). If you piles of it, it is a warning of a scandal that you can change by changing your attitude for a bad situation. If it involves someone else's trash, it foretells of trying to help another person out of trouble they've caused for themselves, or their reputation.