Unfortunately, when you donate a single item or group of similar items with the value of more than $5000, you must have a signed appraisal from a qualified appraiser. You must also have a form 8283 for the charity donation signed by a financially responsible representative of the charity acknowledging the receipt of the donation. For any donation, including the smallest donation of personal property, you need your own list of the items in sufficient detail to allow you to determine the donation value. The list should typically include the purchase price, the date of purchase, and a description of the item in sufficient detail that allows you to determine a fair market value. With inherited property, the value of your donation is the fair market value on the date of your mothers death, and you don't need to know her original purchase price, because your cost basis is also the fair market value on the date of her death. But you still need some reasonable and legitimate way to determine what the fair market value was, and this will normally require a list of items with sufficient detail that you can determine the quality, condition, or otherwise determine the value.
If you at least have a complete written inventory, then you will need to start by grouping the inventory items into "groups of similar items." This might be; household goods, furniture, clothing, jewelry, etc. enter each group as a custom item listing in TurboTax claiming no more than $4999 per group. Desperately hope and pray that you do not get audited.
If you don't have a detailed physical inventory of the items, I have no idea what you are going to do to substantiate your charitable donation.
