Step 1: The question is taken directly from the poem "Polythene Bag" by Durga Prasad Panda.
Step 2: The poem uses the characteristics of a polythene bag as a metaphor for human hurt that never truly disappears.
Step 3: One of the key physical properties mentioned in the poem is what happens when the bag is warmed. The poem states that "When touched it makes a squeaky noise, / when burnt it exudes a pungent smell, / when left to itself it pollutes the environment." However, the line "a little warmth" makes it 'melt down'. This melting is compared to the way hurt can soften but still remain.