I have a set of KEM 100% plastic playing cards (stargazers model). They're a premium brand and supposed to be long lasting but after opening the box after not using them for some time I discovered that the top card of each deck (10 of clubs and Ace of diamonds) had warped whilst the rest of the deck hadn't.

Manipulating them with my hands, I haven't been able to flatten them out. There is so much spring in them that they are easily identifiable even in the middle of the deck where they will cause the cards above to lift up.

Does anyone know how to flatten or significantly reduce the warping in these type of cards?

  • I see no way of flattening the plastic card(s) to a pristine condition. The anonymity has been compromised for games of chance; but, they are still usable for some card games of skill. Have you contacted the KEM (?) company for a possible specific card replacement which might be less than replacing the whole set?
    – Stan
    Jan 29, 2018 at 18:36

4 Answers 4


When facing bent cards, I usually do one of two things: Unbend them, or press them flat.


Usually bent cards can be made straight by bending them the other way of the original bend. In some cases running them over an edge curving them against the bend could be helpful.

Applying pressure

In some stubborn cases I've resorted to putting cards in a book, and then some more books on top of this for extra weight and pressure. Leave over night, and the cards are often good to go.

I've never had to use extra heat to flatten cards, but if I should try that I would use a pan filled with warm water from the spring/tap. Put on top of cards and leave over night.


I've seen a method: 2 cards at a time, side by side, between a double-folded layer of parchment paper, on a hard flat heat-resistant surface, clothes iron on lowest setting, and pressing no more that 6-7 seconds, letting cool, and repeating on the other side of necessary.

Problem with Kem cards is that they are sensitive to humidity... Excessive soaking with water will make them unstable. Cleaning is best achieved wiping with baby powder.


I just used this technique to flatten bent vinyl.
It worked.
It (or a similar technique) might work as advertised for your plastic "KEM" card.
My "problem" had no sharp folds, it was simply bent a bit "wavy."
I don't know what "KEM" card plastic is made of either.
Also, my "problem" was thinner than what I would imagine a plastic "KEM" card would be.

  1. Sandwich the rumpled piece of vinyl between two sheets of "picture-frame" glass

  2. Clamp the sandwich layers firmly together flat with spring paper clamps
    If you break the glass with the pressure of the clamps, maybe they were too strong.
    You can see the points of contact through the glass

  3. Run hot (70°C/145°F) water over both sides of the area to heat it up evenly.
    I used the (very) hottest water that comes from my kitchen sink faucet.
    I alternated heating sides several seconds at a time.
    If water damage is a concern, put the piece inside a sealed water-proof plastic bag before you sandwich it. The plastic bags will probably add to the time it takes to heat things up.
    Avoid wrinkles or folds.
    It's a good idea to let the thick sealed edge lie outside the glass sheets.
    You'll see how it works.

  4. And last, Set aside the assembly to cool completely before removing the piece for inspection.


Try using a clothes iron. The idea being that the heat will loosen up the plastic while the iron pushes it flat. Keep the iron on a low temperature. The important thing is that after you have heated up the card, you turn the iron off and leave it resting on the card. Let the iron cool to room temperature before taking off the card.

Note, as this might totally ruin your card, maybe try it on a joker or something first.

  • 1
    Using some heat sounds good. An iron, not so good. Way too hot! I did rather try with a bowl/pan/pot of warm water from the spring to begin with.
    – holroy
    Jul 3, 2015 at 6:44
  • That sounds like a good idea Holroy. I can increasethe temperature in stages then.
    – Dave
    Jul 3, 2015 at 9:34
  • 1
    I would suggest using paper or cloth to protect from sticking to the iron.
    – Terry
    Jul 3, 2015 at 11:47

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