1. How to make alu foil packagesBy
Ivona

2. 1. Pre-cut heavier aluminum foil, to a square size 3x2 inch.

3. 2. Fold the alu foil, to get 1. 5x2 inch package
2. Fold the alu foil, to get 1.5x2 inch package. Make sure you leave a small lip at the opening (do not make both side of the fold equal) so you can see where the opening is and you can open it up with tweezers.
lip

4. 3. Now fold the sides of the package, make sure that the fold is not wider than the tweezers.

5. 4. This is how the fully folded package looks like – I pulled red line along the side folds so you can see them

6. 5. It should be able to fit a un-folded GF/F 25mm filter, as well as the folded one (see image)

7. 6. Once you are done with filtering, fold the top opening, label it on both sides and drop it into the liquid nitrogen or store it in freezer.