[R-390] Squeaky Slugs

[Barry]

I have a squeaky slug and I'm pretty sure it's due to the spring being bent/distorted.  I'm wondering if it's possible to straighten a spring without causing it to "let go" of the slug.  If not, I think I recall reading where talcum powder can be used to lubricate the core.  Is that still a good approach?  I know a liquid lubricant is a no-no but not sure what else is best.

Thanks,
Barry - N4BUQ