Light Shades

Mostly cloth / fabric tones, usually at night, smelling ammonia type. Is this due to dust heating / burning but have tried in vain to dusting. What causes this and is there an easy solution.

Use a compact fluorescent bulb. It will run cooler and do not create the odor.

Yes its due to dust the bulb is burned.
I live in a dusty part of Spain and I am always dust the bulbs, but still manage to collect dust and smell horrible, so I dust the bulb, then turn the light on it No has no odor.
Edit
Another thought your power lamp may be too strong for the shadow so it is heated and the dye in the fabric is the smell.

Well, I've never experienced this before, so that the dust to burn a light bulb could explain the smell. However, because house dust is mainly the skin of man, I find that quite unlikely. In addition, if the shade were getting enough heat to burn the dust, I thought that this material can burn. It is more likely are small insects, mites, etc. on light burns and giving ammonia. Or perhaps died in the material or may absorb odors imperceptible during the day and release them in concentration when the bulb is on?
Have you thought about trying a low-energy bulb that are not so hot and probably would at least reduce the odor, if not eliminated?

probably dust, make sure its dust. I saw a tip about Kim and Aggie last week they put some fabric softener on a rag and wipe the shade when it heats up the room smells good as his anti static dust would help prevent a bit. Hope this helps.

I would say that changing the accessories, where the bulbs go. They could deteriorate and burning, causing the odor.
Just look at little inside the lampshade, make sure there are no traces of burning. If there is, of course, stop using them immediately.
If they are stained within the shadow, perhaps the dyes react to the heat of the bulb.