According to page 167 of John Rich's new book
Warm Up the Snake, the show offered a monetary prize for good MacGyverism ideas they could use in the show.
The story goes that a young fan of the series suggested that MacGyver could patch up a vehicle's radiator by cracking egg whites into the radiator. This trick was used in the
Bushmaster episode and the young fan was rewarded.
Although they had staff appointed to read all the letters sent in for this competition, few usable ideas where ever obtained through this method.
sourced from Wikipedia