The short answer is, maybe a partial deduction.
The long answer is that you can take a deduction for the fair market value of the item as of the date the previous owner died. The fair market value is what a knowledgable buyer would pay a knowledgable seller in an open sale, for the same or similar item in similar condition (used good, fair, etc.). It's the paperwork that will hold you up.
For any donation of a single item or "group of similar items" valued at more than $5,000, you need to have a signed appraisal from a qualified appraiser, and you need to have a copy of form 8283 documenting the donation that is signed by a representative of the charity. The IRS does not specify what makes a "group of similar items." Possibly, you could try and group your items into smaller "groups of similar items" (clothing, furniture, etc.) to keep each group under $5000, but this could present an audit risk.
You also can't claim any deduction for items in "poor" condition unless you have a signed appraisal, even if the item is less than $5000.
Then, for any donation of items, you need at a minimum,
1. A written description of the items in sufficient detail that you can determine the fair market value. Also include how you received the item and the date (by inheritance, and the date of the previous owner's death).
2. An acknowledgment or receipt from the charity showing you donated the items on your list.
3. Documentation of the method you used to determine the fair market value.
So at a minimum, you need some kind of written inventory to use a proof of what you donated, and to calculate the value, and you need a receipt or acknowledgment from the charity. And you can't claim more than $5000 unless you have the additional documents. If audited, the IRS will be looking for evidence that your inventory is accurate and reliable, and for proof that you actually donated the items on the list.
The detailed rules are here.
https://www.irs.gov/forms-pubs/about-publication-526
