[mike]

You can get rid of the yellowing easily, if it occurs.

 

And on the subject of radioactive elements. When elements decay, they become other isotopes/elements, which may emit other radiation when they decay. So more than likely, they will emit gamma, alpha and beta radiation.

 

And on ICs from the 70's, I have not heard of radioactive elements in those. As far as I know, they used the same stuff as they do now (silicon, gold).

 

In IC it was the chip packaging material. In particular, it caused DRAM caps to discharge.