A long time ago, back in my Iron butt days, I went to an audiologist, and $54 + 1 week later I had a silicone custom-formed set of ear plugs.
He said to come back if they didnt work. I should have.
One fit snugly, and blocked out as much noise as the foam rolluppy ones, the other was close but not as tight.
They were very comfortable, water or spit was required to help them in easily, but not always necessary.
Note that I'm comparing them to the foamy rollluppy ones - those are the 'quietest' earplugs I've ever used, in Ironbutt land or in occupational OSHA-controlled land.
I like how the foamies 'remove' ear wax also.
I got an ear infection about 6mo after staring work at the power plant - I will never re-use earplugs again without some kinda wash every time, and even then...
If the foamies got a bit dirty from my fingers, I mititagated that by throwing them out and always rolling a new pair (they are pretty cheap in bulk). The fact that the are the quietest (my observation only, no science to back me up...) makes me want to stick with them.
-John