goatsrunfaster

Hello Everyone, Im working on a project where Im trying to extract DNA from recently fixed fish specimens stored in Formalin. The problem is that formalin degrades DNA. I was wondering if anyone here might be able to interject with what might be the least penetrable (most dense) organ in the human body (which would likely be the same for fish), one that would potentially take the longest to be penetrated by the formalin. Maybe there is an organ thats not so dense, but would some how keep the formalin from penetrating the interior? Basically something that is in-penetrable by liquid on the outside???... Any help or even suggestions would be greatly appreciated. Best, Spencer