I think this depends on the nature of the shitcoin that forks off.

If there's rule changes in transaction op codes could prepare a tx that is valid by the shitcoin but not Bitcoin, sign with CC, and broadcast that to the shitcoin network to move funds.

If it's from a change in subsidy amount, then could buy a small amount of it from blocks that came after the fork as those shitcoin utxos wouldnt be valid under Bitcoin and then you could create a tx spending that as input and prefork Bitcoin safe in the knowledge that Bitcoin would reject the tx while the shitcoin would accept.

Probably other ways. I don't have experience with it as I'm still a newb.