Inevitably, we tip open bottles of fluids when they are filled with the worst possible stuff, Acetone, Lacquer thinner, glues, DCM, etc.
A magnet, and two cups can prevent a big mess.
We need:
- A 1 inch ‘Rare-Earth’ ring magnet
- Two tapered plastic medicine cups (Note: glass will shatter)
Since the ring magnet is open in the middle, any discontinuity on the bottom of the medicine cups will not tilt the magnet.
Got to get a new brush 
BTW plastic medicine cups are great for mixing epoxies and other glues.
‘Acetone’ is great at removing the most stubborn flux residues on your PCBs.
Make sure it does not affect your components and solder masks.
I have not found it harmful on PCB solder masks.
Many industrial flux removers are 50:50 Acetone and IPA.
‘Lacquer Thinner’ works well at removing flux buildup too.
