Starter contacts are repairable all Toyota starters. They are the only part that normally wears out and are available, for most models from the Toyota dealers parts department. Some older models are not available but if you look in the phone book under auto electrical repair they will have what you need.
The following came from a great page for 4X4 owners. I have to admit that I "borrowed the images" so being lazy and not owning a digital camera it was the next best thing.
You will have to remove the starter from the vehicle.
Once you have it off you need to take the end cover off the solenoid, its best to use a 8mm wrench or socket. Once the cover is off you can take out the plunger and spring. The plunger will look like this, really normal.
You can then see inside the solenoid to the contacts. Its the wear on these combined with the burned surface on the plunger that is causing those clicks when you go to start the engine.
The contacts shown are both new (bright) and old (dark). If you look closely you will see on the old one there is an area worn away on the flat surface that contacts the plunger. Its this extra distance that the plunger need to travel that caused the intermittent connection and the clicks.
Clean up the plunger as shown.
You need to take off the contacts from the large bolts on the starter case and "tap off the old contacts" from the bolts. You install the new contacts the same way. You will see that there are some insulators protecting bolts from the metal case. Its important not to forget to reinstall these the way they came off.
When finishing the insulation of the contacts make sure that they are sitting flat in the starter. If they are not, (and in tightening the lock bolts they can twist) the starter will click again after a couple of days.
The kit that needs to be replaced are the positive side and the negative side. Toyota sells them separately. The positive side part number starts with 28226-16130 (this is an example for a JPP Corolla 92-97). The negative side would be 28226-74070 (for the same vehicle). Not all are the same, but with this example the parts dept. (if they did not know of this kit) will have a place to start.