I have the inside edge of my front tires wearing out & the mechanic says, the 91 accord cannot be aligned!!! how do i fix this?

If it is only wearing on the inside edge your wheel alignment is wrong. The most common cause is the tyre is 'toe out'. The tyre isn't pointing straight ahead like the one on the other side. It is sticking out at the front edge.
Take the car to a good tyre and suspension specialist and get your 'tracking' and 'alignment' checked. They should check your track rod ends and suspension mounts as well.

If you are confident the wheel alignment is correct (first option) it may have excessive positive camber (lean in or out of the front wheel). This is often adjusted at the top of the strut tower (if fitted). A good front end mechanic would fix this problem in his sleep, you would not have to prompt him.
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Under inflation. When the tire doesn't have enough air pressure, the center tends to be pushed up from the road. Thus causing outer wear on both sides. alignment problems cause wear on one side or the other. Over inflation causes the center of the tire to wear .

tires need to be balanced that will fix vibration. tire wear is a camber problem. get a four wheel alignment

Strange.
Has anyone checked the front end alignment on a rack ?
Usually when the tires wear on the inside edges the camber is off and the tires are running on the inside edge more than the outside.
Or the front suspension is too low or heavy.

It sound like the Camber is off in the rear. Did you have an alignment done after the new struts wear installed?

Sounds like you should have the alignment checked on an alignment machine on all 4 wheels.Once you get those readings and an expert alignment mechanic's estimate on repair,only then will you know the correct repairs needed.

I'm guessing the lower ball joints are shot. This will cause the tires to lean in on the top and and wear the inside of the tire. I could be wrong! Try jacking the front wheels up and support the vehicle on jack stands, now grab the tire top and bottom and try to rock it in and out. If there is movement, you will have to have someone watch to see what is moving, while you rock it. If it's the ball joints, they will need to be replaced before you can align it. This can be spendy, there's a lot of labor involved.

Tire riding on the inside edge means camber issue. Take it to another shop. Camber adjustment kits are available several places. Here is one example: http://www.stillen.com/product.asp?id=STICMBR01&c=SU&r=&b=&m=all

The factory didn't build enough adjustment into some vehicles. My Mustang GT has a similar issue easily fixed with an adjustment kit. Kit needs to be installed and vehicle re-aligned.

Hope this helps.

Bob

Your situation is not not abnormal. Since you can't rotate due to different sizes front & rear & they are high performance "Y" speed rated tires 30K is really pretty good