If it were me, I would disassemble all brake lines and clean them with brake clean, then run multiple flushes of new fluid through. I really wouldn’t recommend switching between glycol and silicone based fluids though.

Geoff

1955 2nd Series 3600 235 cid, 4 sp. - Current
1979 Chevy K10 350 cid 4 sp -Sold
1955 2nd Series Wide Window 283 cid 3 sp - Totaled