Generally it is save to work with magnesium. The rod can not be ignited with means a boy scout would have. The shavings however are easily ignited. It would be a good idea to enforce a rule against sparks and open fire until the cleaning is done. Iīd make the kids collect the shavings and try the firestarting with them.
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If it isnīt broken, it doesnīt have enough features yet.