It is brute force, and patience. Just keep twisting them and pulling on them, and they'll very slowly slowly slowly work themselves off of the bar. I twist clockwise while pulling at the same time. It can take FOREVER if they're on there tightly enough.

This is a job for ...

Seriously ...

thanks, iconomy. I'll try it. I assume that means putting them back on is just brute force, too, then?

You might try using aerosol hairspray or rubbing alcohol or another short-term lubricant (or, if by some chance you've got easy access to one, an air compressor). And, usually, I find that if I twist and move the grips where they're closest to the stem, kind of breaking the seal between grip and bar, and then push toward the end of the bar, seeking to compress the grip a little, it comes off more easily. Where too much twisting and stretching, on the other hand, means that the grip never quite fits well again, and, when I put them back on, I wind up using sandpaper or adhesive or zip-ties or something. YMMV, and you might consider Lock-On grips in the future--the Oury ones are probably my favorites.

thanks! alcohol isn't bad for it?

I can't switch grips very easily because the gear shifter is built into it.

The alcohol evaporates pretty quickly (and we're talking about a very thin layer), but I'd keep it away from anything with oil/grease on it.

The gear shifter is built into the grips? Like GripShift, or something similar? In that case, are you sure that there isn't a tiny bolt which must be opened before sliding the shifter-part (as opposed to the stationary part) off? I'm kind of an old-school, retro-grouch bicyclist, and so I'm no GripShift expert, but I seem to recall working on one of 'em, years ago, and, if I remember correctly, that's how it goes.

It's called Spectro Sachs. I can't find a picture of it. But thanks for mentioning the bolt- it does look there is one.

hmm. upon further research, yes, it does seem to be related to the Grip Shifter family and seems to be called a twist grip shifter.