Actually, we don’t even need to clean up 60%.
First, the methane will dissipate.
Secondly the lighter molecular weight aromatic hydrocarbons will evaporate.
Thirdly a portion will emulsify and/or be metabolized in the sea water.
What’s left needs to be cleaned up — the goo, the tar.
IT’s a mess for sure.
THere is a solution to that in the works, too. With Cap and Trade, people will hunt for tarballs to burn to keep warm this winter...