I have just bought my first boat and am in the process of going thru everything. In draining the fuel tank ( Johnson Mile master 6 US gallons)I came accross about a cup of grit. Having never dealt with fuel tanks before I come here before I started tearing it apart to get the do's and dont's. such as what kind of material should I use to replace the gasket, should I put some kind of sealer on the inside of the tank any other pertinate information would be appreciated.