Your techniques for cleaning flybacks

[Phil]

Several times I have broken wires on
Flybacks trying to clean 70 years of
Crud from flybacks. For that reason
I like to find NOS replacements
When possible. I would be interested
To know what techniques other, more
Experienced collectors have developed
To eliminate the baked on dirt
Without damaging the flyback.
I appreciate your responses
Greatly and hope your methods
May also be helpful to other
Restorers. Thanks.