So, I've read to make the ingots, you just grab a load of Dwemer Metal Items from the ruins and smelt them into ingots at furnaces.

However, between me and Faendal we were carrying HUNDREDS of Dwemer items, but at the furnaces there was no option to smelt these into the ingots! How on earth do you do it?

If it starts with the word Dwemer, it can't be smelted (so Dwemer scrap metal, gyros, dishes and stuff are unusable). The ones you can use:

• Bent Dwemer Scrap Metal
• Large Decorative Dwemer Strut
• Large Dwemer Plate Metal
• Large Dwemer Strut
• Small Dwemer Plate Metal
• Solid Dwemer Metal

http://www.uesp.net/wiki/Skyrim:Dwarven

I hope that this will help you.

Smelting only works with: Bent Dwemer Scrap Metal / Large Decorative Dwemer Strut / Large Dwemer Plate Metal/ Large Dwemer Strut / Small Dwemer Plate Metal / Solid Dwemer Metal

Bent Dwemer Scrap Metal, Large Dwemer Plate Metal and Small Dwemer Plate Metal have the "best weight to ingot" ratio. (good to know if you plan to raid some ruins)