I agree with Symptoms, except i would probably choose a piece of mild steel bar insead of a screwdriver. Use a foot or so of bar, and bend the end into a handle like a sardine tin key. If the jets are brass, mild steel would probably be adequate.
My experience of modifying screwdrivers is, except for the very cheap ones, the whole blade is hardened, and only the tip is tempered to stop it shattering.
Or you could cut the tip profile into the end of a long bolt. A high tensile bolt is usually soft enough to saw or file, but tougher than mild steel in use.
Another way would be a bit of hex bar the same size as an interchangable screwdriver bit.
I was thinking of suggesting an old screwdriver bit, but they are usually too hard to file to shape, unless you can anneal them first.