401k-how to purify

AsalamuAlaikum

I have had a 401k for 10 years. The main holding is a mutual fund ( FGCKX)

It has grown substantially, however, I am unsure of the Shariah compliance of the fund due to it having 100s of holdings.

I know I have to find a Shariah compliant fund and do a rollover to an IRA potentially.

What is the safest thing to do in order to purify the money before I move it? Is there a calculation I can do? OR do I get rid of everything except for the amount I originally contributed (that will mean keeping only 30% of current balance).

This is an issue that has been giving me worries for a year. I do not know what to do. And the more I wait, the more impure money is being added on.

JazakAllahu Khairan

Please is there any way the Mufti can answer so I can figure out what to do with my 401K?