The ends of the Brush Magnet are strongly magnetic. The inside is sturdy and flexible, therefore the clip stays in the position you bend it.Thus it fits on any container, bucket or paint can.The outside is of a soft rubbery plastic, which will not damage the brush and can.
You can reuse a liner at least 2 to 4 times, even with a different color of paint, provided it dries properly. Some painters use a liner as many as 10 times, after emptying and drying it thoroughly. Replace your liner in any case when paint particles start coming loose, or preferably before.