C.R.S. § 30-20-1003

(1) A retailer selling replacement lead-acid batteries in the state may: (a) Accept from customers, at the point of transfer, used lead-acid batteries of the same general type and in a quantity at least equal to the number of new batteries purchased, if offered by customers; and (b) Collect a deposit of at least ten dollars on the sale of an automotive-type replacement lead-acid battery that is not accompanied by the return of a used lead-acid battery of the same general type. All deposits shall inure to the benefit of the retailer unless the person paying the deposit pursuant to this subsection (1) returns a used automotive lead-acid battery to the retailer within thirty days of the date of sale, in which case the deposit shall be returned to the customer.