It is unlawful to place, pile or to cause or permit to be placed or piled any sand, gravel, cement, plaster, concrete or any other substance or mixture or to allow the same to remain on any portion of any paved street or sidewalk in the City. No person shall make, mix or cause or permit to be made or mixed any mortar, plaster, concrete or any other like substance or mixture on any portion of any paved street or sidewalk in the City; provided, that in cases where work is being done on buildings or pavements, the Public Works Director may grant the person or contractor doing such work permission to mix cement, concrete or building materials in tight boxes or on tightly joined boards on such pavements or walks under such restrictions as the Public Works Director may deem proper. The fee for a permit under this section shall be in an amount as determined by the Mayor in a written policy, to cover the actual costs of the City. (Ord. 18-06)