Write a suitable term for the following description.
Naphthalene balls reduce in size on long standing

Explanation

### Step-by-Step Solution:

1. **Understanding the Description**: The question describes a phenomenon where naphthalene balls reduce in size when left standing for a long time. This indicates a change in the state of matter.

2. **Identifying the Substance**: Naphthalene is a solid substance commonly found in naphthalene balls, which are often used as mothballs.

3. **Observing the Change**: When naphthalene balls are left out, they gradually decrease in size. This suggests that they are losing material over time.

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