I just bought a 1/48 Avro Anson, which contains many resin pieces, including two brittle cowlings with thick casting blocks attached. These can't be replaced if I damage them, short of buying another kit, and I don't know what kind of tool I need to remove the blocks. Can someone please help me?

I used a fresh Xacto blade to carefully scribe the cut line a couple of times then a small razor-saw to cut along the scribe working from either end towards the middle. Slowly does it.

I do it the same way , just make sure you wear a MASK , the dust is very , very toxic to your lungs !

Thanks! There's an Ace Hardware across the street, I'm sure they'll have everything I need.

What is so bad about resin dust as opposed to all the other particulates we expose ourselves to. It is worse than styrene dust, paint spray?

Correct me if I'm wrong, but I'm under the impression that while the properly cured resin itself is inert and safe, it's the extremely small size of the dust particles it makes when sanded that should be avoided.
Being so small, they can end up in one's lungs and cause complications in the long run.

But any particulates you sand off any material is is only as fine as the thing you are using to sand it. If you are worried, which I am not, wet the area you are going to sand. And wear a mask as well if you want. Paint outgassing is far more toxic than resin dust and enamel paints used to give me headaches when I was young. I don't use them anymore and only use acrylics... well until I got a poo-load of Mr Color paints recently for very cheap.. $1 a pot!!

The best tool I have found for cutting resin and plastic is the JLC saw. The blades are VERY thin and sharp, allowing very clean and close cuts. Sometimes I use the blade by itself for odd angles or hard to reach places.

I think most resins used for models are polyurethanes. http://en.wikipedia.org/wiki/Polyurethane

Although the dust can smell a lot, I don't think this necessarily means it is any more harmful than any other particulate. But as all small particulates should be avoided, wet-sanding is a sensible precaution.

My experience of cutting free parts is to be patient- work slowly with a razor saw. I have at times got impatient and thought "I'll just cut through the last bit with a blade" and it usually ends in the part cracking, or the blade eating into the part being freed.