Should i invest in my home principal?

Should i invest in my home principal?
Added (1). Should I invest in my home principal?
Added (2). I am about to sell my house, and I have about $20000 in my savings account. So I am thinking of paying the $20,000 towards my principal to help remove the PMI on my mortgage and reduce the interest i am paying on my monthly mortgage. Since i am trying to sell the house, is it worth investing the $20,000 toward the principal?

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