Personal property belonging to the Town may be sold or disposed of by the board, officer or head of the department having charge of such property only if in conformity with the following conditions:
A. 
If its value at the time of the proposed sale or disposition is less than $500, upon specified authorization, in writing, by the Town Administrator; or
B. 
If its value at the time of the proposed sale or disposition is $500 or more, upon specified authorization, in writing, by the Board of Selectmen and in accordance with the provisions of MGL c. 30B.