The county government may require that each bid for the bonds be accompanied by a certified check in the amount of 10 percent of the bid. After the bonds are awarded or sold to the successful bidder or bidders therefor, the county government shall return to the unsuccessful bidder or bidders the certified check or checks submitted with the bid or bids.

48 Del. Laws, c. 331, § ?14; 9 Del. C. 1953, § ?565; 55 Del. Laws, c. 85, § ?4A;