Answer

Yes, you may use the lehenga for pooja after washing it properly, if it becomes clean and is suitable to wear respectfully for pooja.

Explanation

In Jain practice, clothes worn for pooja should be:

• Clean
• Freshly washed if they became impure or dirty
• Free from food stains, smell, or uncleanness
• Worn with a respectful and devotional feeling

If you had lunch while wearing that lehenga, then it is better to wash it first before using it for pooja.

Spiritual Understanding

Pooja is done with purity of body, clothes, and mind. Clean clothes help create a feeling of respect, discipline, and devotion toward Bhagwan.

Takeaway

Wash the lehenga properly, make sure it is clean and fresh, and then you can wear it for pooja.