In order to calculate the value of the Gold-filled scrap, we need to know what type of Gold filled do we have.
The most common is Gold filled is 14K/20, in which, the ratio between the 14K gold and the brass is 1/20 (5% of the wieght).
For example, 100 gr. of scrap type 14K/20, will contain;
(14/24) X 1/20 = 2.925% Fine Gold
* Remember, the first number is the Gold Karat and second number is the ratio between Gold alloy & Brass, so, 9K/10 – is 9K Gold with ratio 1/10
For your convenience, bellow please find, Value Calculator for Gold filled scraps (all types)