One has to wonder then... what made the Holy Spirit wait? Obviously being cleansed of leprosy would be sign enough, and far more powerful than wet clothes. Why did the Spirit wait until the seventh dip?
Obedience.
Romans 6 is such a great reference to what baptism IS, and I would like to focus on part of it here:
Romans 6:15 What then? Shall we sin because we are not under law but under grace? By no means! 16 Don't you know that when you offer yourselves to someone to obey him as slaves, you are slaves to the one whom you obeywhether you are slaves to sin, which leads to death, or to obedience, which leads to righteousness? 17 But thanks be to God that, though you used to be slaves to sin, you wholeheartedly obeyed the form of teaching to which you were entrusted. 18 You have been set free from sin and have become slaves to righteousness. NIV
Now, as for the removal of dirt: lets visit another scripture:
I Peter 3:18 For Christ died for sins once for all, the righteous for the unrighteous, to bring you to God. He was put to death in the body but made alive by the Spirit, 19 through whom also he went and preached to the spirits in prison 20 who disobeyed long ago when God waited patiently in the days of Noah while the ark was being built. In it only a few people, eight in all, were saved through water, 21 and this water symbolizes baptism that now saves you alsonot the removal of dirt from the body but the pledge of a good conscience toward God. It saves you by the resurrection of Jesus Christ, 22 who has gone into heaven and is at God's right handwith angels, authorities and powers in submission to him. NIV
Again... a simple obedience to God which is a pledge of a good conscience.
Obviously, it's human nature to argue our point: just look at Naaman. We always question simple demands when we don't fully understand how they work. Baptism is truly a miracle. In one simple act of faith, we obey God and receive a new heart. We really can't take credit for it, because it's the Spirit who does all the work. Wow. We can try and tell God that our decision is not really required or that our parent's can decide for us, or that the rivers in our country are far cleaner. But all he is looking for is a simple act of obedience: Repent and be baptised everyone of you calling on his name.
You are almost there... just don't stop after the sixth dip.