What are the ways to harden or preserve the modeling clay?

not put oil based clay oven if don't want melt , maybe burn.

if have oil based clay, means clay designed never harden. way preserve put transparent plastic box protected harm, or put in place doesn't bumped accidentally.

if have different type of modeling clay, there might ways harden it, either air-drying or putting oven. without knowing kind of clay have impossible tell you.

need read package clay came in. have instructions hardening if applies.

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