Here's a tax tip for the industrious among us who are determined to de-clutter the house and make room for guests this holiday season:

Do not expect to clean up on your 2006 federal income tax return by taking a huge deduction after you donate all that junk. The tax rules have changed.

Tighter rules for contributions of clothing and household items took effect during the summer, as part of the Pension Protection Act of 2006.

So if you've given away anything after Aug. 17, you cannot take a deduction for a charitable contribution of clothing or household goods — unless the items are viewed as being in "good used condition or better."

Clunky wording, yes. But these are tax rules. What does "good used condition or better" mean?

"Now, they don't define what that means," said Herbert Hoffman, tax director for BDO Seidman in Troy, Mich.

Not yet anyway. The Internal Revenue Service is expected to give more guidelines later, as we get closer to tax season.

In general, though, we can take an educated guess here and say that you do not have a legitimate tax deduction if you're donating bags of old pants, ratty sweaters and stinky shoes. If it's junk that you would never wear — and junk that no one else would wear, either — do not expect to cut your tax bill by donating it to a charity.

"Don't unload your garbage and take a charitable deduction," Hoffman said.

It may get a little tricky to figure out what qualifies.

"I don't think anyone would want to go out and try to get an appraisal for this stuff," joked Mark Luscombe, analyst for tax publisher CCH in Riverwoods, Ill.

He does advise taxpayers to keep even more pristine records of these donations and take pictures of clothing or household items before donating them to document how good something looks.

Typically, you can deduct the fair market value at the time you gave the item. Or Hoffman suggests basing the deduction on what the item might sell for at a secondhand store.

If you bought a $50 shirt, he said, you couldn't take a $50 deduction once you wear that shirt and then donate it.

A man's shirt might have a value of $2.50 to $12, according to the Salvation Army Valuation Guide at www.satruck.com.

If you plan to donate old underwear or old socks and take a deduction, think twice. The IRS may deny a deduction for any item that has minimum monetary value, such as socks or underwear.