A lot is sold on trust about uncertainty, which makes honesty about the uncertainty the whole product.
Claiming you have checked it
There are three honest positions — checked and listed, partly checked, unopened — and they are worth different money. Claiming the first while meaning the third is the dispute that follows.
Photographing the closed box
A lot shown closed is a lot nobody bids on. Lay the contents out.
Guessing a count
"Roughly 40" is fine. "40" when it is 28 is not.
Not weighing it
Weight decides the delivery cost, and the difference comes off your balance. Weigh the packed box. Packing a lot.
Leaving restricted items in
Wildlife products, antiquities, weapons, medicines, anything needing a licence. "It came in the lot" is not an exception. Prohibited items.
Leaving personal papers in
Letters, photographs and documents belong to a family rather than to a sale. Take them out.
Burying something valuable
Pull out anything identified and run it alone. A lot drags it down and somebody always notices.
The one that costs most
Not writing what is not guaranteed. One sentence — electricals untested, chips unchecked, nothing identified — and most arguments never start. Describing a lot.
Questions people ask
Can I sell an unopened box?
Yes, described as unopened, with its weight and size.
Is sorting worth the hour?
It is the most profitable hour in this category. Themed lots beat mixed ones.
What if something valuable turns up after?
It went with the lot. That is the deal both sides made.