you can not deduct any sales tax. To claim the tax for these items, you must keep adequate records that support the amount you paid. While the IRS does not specifically mandate original paper receipts, you must have enough documentation to prove the tax was paid at the general rate. For home construction or renovations, the rules are more strict and generally require that you pay the tax yourself and not make a reimburement of to the party that actually paid the tax.
Most taxpayers don't know this, but when they are the initial buyers of a home, they are likely reimbursing the contractor for the sale tax paid. Those who know this and want the deduction buy the materials directly ad pay the tax. At least some did it years ago when there was no limit on the tax deduction on schedule A.
