This post has been updated. It was originally published on October 7, 2019.

Those flowers may have looked good when you first received them, but despite your best efforts, you can’t keep them fresh forever. If you really want to preserve your blooms, you need to remove their moisture with a process like air-drying, pressing, or nuking them in the microwave. (You can also try dipping them in wax, but that method is harder to pull off.)

“There are many quirky and unconventional techniques out there,” Alfred Palomares, vice president of merchandising at floral retailer 1-800-Flowers, told Popular Science in an email. “All these ways have the potential to produce beautiful and consistent results.” While you can try any preservation method, each one does have its own pros and cons.

For the traditional: air-drying

To stick with a classic technique, you can simply hang your bouquet upside down. As the air wicks moisture away from the blooms, they should gradually dehydrate.

However, this method can be a little finicky: Flowers may shed their petals, and mold can attack them. Plus, the process takes a few weeks. On the bright side, this drying technique does preserve the flowers’ stems.

To start, you’ll need twine or ribbon, a well-ventilated area out of direct sunlight (like a closet with the door open), a hook or hanger that will support your bouquet’s weight, and, optionally, hairspray.

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If you’d like to experiment with air-drying, wait for your blooms to partially or fully open. Then tie a few of them together by their stems. Fasten them tightly enough that they won’t slip out—as they dry, they may shrink—but loosely enough that they don’t bend the stem, because those compressed areas will be damp and thus attractive to mold.

Next, hang the bouquet upside down in your drying area. Ventilation will help dry the flowers, and a lack of sunlight will reduce the amount that their colors fade. Leave the bundle for two to four weeks, checking back at regular intervals to see how it’s doing. Once your flowers are dry, a quick spritz with hairspray will help prevent them from crumbling too easily.

For the risk-averse: book-pressing

a stack of books on a wood surface
Unfortunately, you can’t press flowers with the sheer weight of human existence, but books do a fine job, too. Photo: Morgan Harper Nichols/Unsplash Morgan Harper Nichols via Unsplash

If you want an easy preservation method, with the least risk of messing up your results, you can press any flower variety in a book. That’s not to say that the process is fast—it can take a month for the petals to fully dry out—but your workload upfront is minimal.

“There’s little effort and upkeep that goes into this technique,” Palomares says, “and the results are consistently wonderful.” The only downside is that pressing works best when you remove the stems.

For this method, you’ll need a heavy hardcover book, such as a dictionary or coffee-table tome, a few sheets of paper or waxed paper, and a pair of scissors.

Start by trimming your flowers down to the heads, removing as much of the stem as possible. Then take the book, open it to the center, and cover the pages with a sheet of paper or waxed paper. Close and reopen the book to crease the liner layer so it will stay in place. Finally, place the bud close to the middle of one of the pages, press the bud flat on the paper, and close the book.

Over time, the liner paper or waxed paper will absorb moisture from the flower, gradually desiccating it. Check your flower’s progress once a week or so, replacing the liner paper to give it a fresh dry surface. After four to five weeks, you’ll have a dried blossom that should last indefinitely.

For impatient driers: silica gel

If you want results fast, you can speed up the drying process. However, these techniques require that you pay more attention to the flowers. You can sometimes over-dry them, resulting in fragile blooms that can crumble all too easily.

For a speedy version of the air-drying method, cover your blossoms in a moisture-absorbing desiccant like silica gel, which is made up of silicon dioxide, a key component of sand. Although silica gel can be expensive, you can always reuse it. In addition to the gel itself, you’ll need an air-tight flat-bottomed container, such as a jar or piece of Tupperware.

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Pour some silica gel into the bottom of your container to form a layer between 1/2 inch and 1 inch thick. Add a layer of flowers, and then pour more gel on top, making sure it gets in between the petals, until the blossoms are completely covered. Pop the lid back on the container, and leave it for a couple of days.

Check on the dried flowers every two days, for up to a couple weeks, until they feel dry. Then remove them, brush off any remaining sticky gel, and save the leftover silica for another day. You can keep using it until it turns pink, indicating it has lost its moisture-absorbing abilities.

For impatient pressers: microwave pressing

Just as silica acts like a speedy version of the air-drying technique, you can use microwaves in an update of the pressing method. As the microwave radiation heats up the liquid inside flowers, it escapes as vapor, drying the blooms.

“While it may seem unusual, pressing flowers in a microwave is a perfectly safe and quick option for those looking to save time and resources,” says Palomares. However, he says, “Like any shortcut, there’s a slightly higher chance of this method producing mixed results when compared to the others.”

For this option, you’ll need two microwave-safe ceramic plates, several coffee filters, and, of course, a microwave.

To start, layer your materials in this order: face-up plate, coffee filter, flower, coffee filter, face-up plate. Pop this sandwich into the microwave for one minute, then take it out, check the dryness of the flower, and replace the coffee filters with fresh ones. Repeat this process until the blossom is as dry as you want it to be.

All the techniques can turn your flowers from ephemera into mementos. Try experimenting with a couple of different methods to see which one gives you the best results.