How can we prevent Use Tax accrual or messages about Sales Tax on Voucher entry?

We are currently in 9.1 and are moving to 9.2 the first of next year.  We do not currently, nor do we intend to use a third party tool for Sales and Use Tax in the near future.  We are handling the Sales and Use Tax accruals using a different process.  Our Ship To locations are set-up as "Exempt" for Sales/Use Tax Applicability and our Payables Options > Sales Tax Tolerance is set to 100% and an amount of 1,000,000.00.  We have been trying to prevent the system from accruing any Use Tax on vouchers where there was no Sales