Banana plant aphids

Hi there,

I wondered if anyone had any tips on getting rid of aphids on banana plants.

I brought my Japanese bananas inside for the winter and one is fine but the other one has aphids and is looking very sad. Im worried they have damaged the new leaf. 

I'be tried spraying it with soapy water which seems to work a bit but they come back and I'm not sure the plant likes it much.

thank you!

Cat