Advice needed on softening a Canadian helmet liner

[Haplo]

I have tried using sillicone spray on a old and really hardend liner.
It worked rather well and stayed supple for about a 2 years.
After 2 years it still wasn't as hard as before.
Tried a few things on that liner and this worked out best by far.

[Infanteer]

I suppose it all depends on why you are looking to soften the liner. Do you want to soften the liner by any means possible just to have a soft liner or are you concerned about preserving the item for the future? Sure, there may be products that will provide a short term (relatively) desirable effect but often these products also cause irreversible long term damage. In the end it's your item so do what you want but many of us would rather conserve the items in our collections and think long term. To each his own.

[24th_infantry]

Thanks for all the help! I'll just leave it as is. I'd rather not do more damage to it.