I have a 1943 wheat penney. It is very dirty so before I send…

it is commonly believed that you cannot clean coins without damaging or reducing their value. However, if you ever so gently used a drop of dish detergent and lukewarm water with an extremely soft cloth, you could probably remove the dirt and grease without removing the desired layer of oxidation that gives us a coin it's character. Since your coin is probably not gonna be worth more than a quarter under any circumstance, it's a good one to practice with.