WD-40 Penetrant
WD-40 Professional Penetrant Spray, 11 Oz - Rust Breaker with Smart Spray Design
You will find that the plastic is resistant to saltwater, making it ideal for marine environments.
Fast-Acting 11oz Penetrant with Dual Spray Options - 6 Cans for Industrial Use
You will find that this unbranded accessory fits standard setups without any issues.