For anyone not sure about the pens by a company named Pilot, the Frixion pens. They are amazing. See for yourself:

You can get the pens in 8 colors
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They write not bad, like pen more than a marker
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Want to get rid of the pen marks? Just iron. Any setting will do!
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And TAAADAAAA! Gone. Wherever the heat touches, it's gone.
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And another picture of my little goober.
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