I have also had good luck reusing yeast. I simply poured the slurry in
a clean mason jar.I made 3 g marigold wine. Before too long I had
harvested enough flowers to begin another 3 gal batch. Used the left
over slurry to begin the new batch.

I have also had a difficult to ferment port.
When I racked my strawberry wine, I added some of the remaining sludge
to the port and it really took off.