It depends on how rough it is -- you could try an aluminum polish such at Mothers, but you'll have to follow with a brush to clean the polish out of the nooks and crannies. But if it were polished already, then you could certainly use that, even with a PowerBall Mini.
For a stock finish, I'd first try a mild soap solution and a stiff detail brush -- plastic or brass might work best, but experiment in an out-of-the-way place in case you don't like the look. Alternatively, you could try a scrub sponge, or even a fine steel wool.
If you like the way it looks, finish with a careful rinse and a light spray of diluted trim protectant and run the engine until it dries (might as well detail the rest of the engine compartment if you're ambitious).
Your other choice, as I see it, is to remove the intake and have it media blasted, but that's probably too much trouble.
Is this on your '90 LX 2.3?