Lakeland Eco balls - why do they stay there during rinse?

[Mooos]

I can't understand how they work. You put them in, they do the job washing (somehow) but then your washing machine rinses and they are still there. Please can someone explain? I assume they are not soapy but what are they then.

I found they didn't work really.

Yeah good one Moos I'd like to know that one; mine works well and the clothes ARE rinsed but i don't know how either

do they just bash the clothes around?

lol at name Zimblebert! Well they must bash them around but DH googled them and they have tiny detergent balls inside.