Water down and stir your paint thoroughly. Use clean water and make sure you stir up the often dried up paint in the bottom of the pot.
Pour paint into bottle carefully. Use a funnel if you have one small enough. But with a steady hand you can avoid having to clean a funnel, it is not very hard to pour since it is thick and slow.
Clean up any paint that got on the sides of the bottle and put on the dropper top and cap, then remove the label from the old pot. This should be very easy, it just comes right off. Don't touch the sticky part if you can avoid it.
Fasten the label on the bottle as high up as you can, so it is not obscured when sitting in a paint rack.