Toyota Repair: EGR Passage Clogged, speedometer cable, smog test

Question
The car I;m currently trying to unclog the egr passage is a 1982 Totota Corolla with a 3TC engine. . . . I have asked a few people 2 of which where mechanics 1 is a retired mechanic teaching at a local college and the other is a 25 year mechanic and is unknown what he currently is doing, 1 said to use either a transmission cable and the other said to use a speedometer cable, if this is true then how long should i cut the cable so that it will not bind while feeding it into the passage.  I have tried a plastic cable tie andthe results were pretty impressive because the plastic tie was able to get what I think is all the way to the clog but only thing is that the tie didnt have a metal point on the end so that it cannont chip and poke at the clog.  Apparently something must going on because when I poked at the clog with carb ckeaner in the passage the cleaner turned almost completely black, probably from the carbon.  Point being is will the speedometer cable when used properly work in cleaning the clog so that my emmisions level can fall low enough so that I can past the upcoming smog test not to mention on the last smog test i didnt past and my mechanic had to treat the clog with top cleaner for a week and dropped low enough where i barely past.

Answer
I haven't seen a 3TC engine in a while but I believe there is a cover on the rear of the cylinder head that exhaust gas passes through, it may help to remove that cover, if not try using the speedo cable like you said, I'm afraid I can't be of much more help because I don't have any resources that go back that far.