Do you already have a buyer lined up? I sent some silver scrap to
http://www.midwestrefineries.com/ and was quite happy with the process. Their weight was good, the purity matched my own estimate, they paid what they said they would pay with no additional fees and they sent a check relatively quickly.
Be aware that precious metals are all weighed in TROY ounces, which are approximately 10% heavier than "normal" ounces. So if you weigh out 11oz on your kitchen scale, that's roughly 10 troy ounces. Also - if you buy jewelry - be sure to discount for all non-gold in the items: Alloying metals (from karat weight), gems, and some fittings (clasps.) Another valuation problem example would be sterling dinnerware - the knives often only have silver handles, and the hollow silver handles are often filled with something else.
Get a small pocket scale to weigh the items before bidding starts (if you can) and discount appropriately.
You will probably want to build up several thousand dollars worth before sending it in.