As an old goat, I've been very stringent on protecting my hearing ability for 30 years and it has paid off. The play-doh type looks like an excellent design but when you mentioned about losing the 'seal' when putting your helemt on, I had to back off since I know exactly what you describe. Lately, I have found some very good foam type from one of those well known home improvement stores. They are a deep purple color and slightly longer than any I've come across before. Once put in my ears, the helmet hasn't yet caused me to lose that seal. I really like them and the price is right....plus, they last long. I actually wash them in diluted shampoo, tamp them dry with a towel, and finish with an hair dryer on low. Only works for 2 cleanings and then they just don't do well anymore.