Any ideas to remove this

I have a customer who has this deck eon cpi deck. The installer never removed the plastic covering from the boards. This has been on the boards for a year.

That is weird and I can’t say I’ve ever come across it. If it was meant to be removed upon or before installation maybe power washing will take care of it. Might take a turbo nozzle to work all the different angles quickly. What have you tried?

Wow!

I have never seen anything like that.
Test spot before price, for sure.

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