What James said. PTFE deformes easily at 250°C, but it will only melt above 320°C. So if it realy melted you have a serious temperature control problem.
Do you have a photo of the molten parts?
Cleaning PLA can be difficult, since it does not dissolve easily. Burning metal parts out can work, though you should only do that outside.
DO NOT burn it out if there is any chance that PTFE is in the mix. Burning PTFE will release toxic chemicals.
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