The golden spoons [were] twelve, full of incense
Which points at the use those spoons or cups were of, namely, to carry incense in them, such as were used on the day of atonement F12:
[weighing] ten [shekels] apiece, after the shekel of the sanctuary;
(See Gill on Numbers 7:14);
all the gold of the spoons [was] twenty [shekels];
which amounted to forty nine ounces, five drachms, scruples, and eight gains, worth about seventy five pounds of our money.
F12 Misn. Yoma, c. 4, 4. & 5, 1.