Step 6: Measure
And your done.
Trays like this measure unknown weight against a known weight. Most of us don't own 1, 5, or 10 gram masses. But we all have coins. And US coins have a weight tolerance to about a hundredth of a gram. Which is more than we need for this project.
US pennies are 3.1 grams, those printed after 1982 are 2.50 grams.
Quarter weighs 5.67 grams
Dime 2.27 grams
nickel 5.00 grams
Now I don't know if the mass of the other coins are date dependent, like the penny. Because of this I prefer to use pennies.
From here I'm sure you can figure out the rest, measure out your rocket fuel and mediate on your MacGyver skill. Have fun!
(I don't know why this photo is slanted, it's really a feature)