CLARIFICATION OF SALES TAX CHARGES REGARDING
TRADE-INS OR EXCHANGES
QUESTION 1:
A customer who pays tax on everything bought from the parts supplier, buys an engine which required a Trade-in of the same type as delivered: 
Is this the correct procedure, when old motor is turned in at time of transaction:
MOTOR$350.00
TAX  21.00
$371.00
LESS TRADE-IN -75.00
BALANCE$296.00
QUESTION 2: 
Would exchanges of brake shoes, batteries, carburetors, starters, alternators, generators, tires or any other item be invoiced and taxable as in above?
 NOTE: You can bill merchandise out at the Exchange price but they must include the tax on value of old cores.
QUESTION 3:
Because the customer does not bring in old starter (or other exchange item) when the rebuilt one is delivered, parts supplier charges a deposit to insure its return. Should sales tax be charged and credited as described below?
ORIGINAL SALE: REBUILT STARTER   $130.00
         DEPOSIT     50.00
                   $180.00
         6% SALES TAX        10.80
         BALANCE   $190.80
QUESTION 3-A:
 In above transaction, customer later returned old starter (or other exchange item) and was credited:
                 STARTER DEPOSIT   $50.00
         SALES TAX           3.00
                           $53.00
In above transaction is it permissible to refund or credit the tax on the deposit?
QUESTION 4:
A parts supplier sells new parts which require a deposit be charged. Sales tax is charged on all items in the transaction--including tax on the deposit. The customer later returns the merchandise, un-used and in salable condition. Wholesaler refunds all the money paid him originally, including tax charged on the items requiring a deposit. Is this the correct procedure?