The only thought I have Joanna is to save your old used bottle with the hanger and transfer the gel to these older bottle and reuse . Whats left in the new bottle could be used up on your first shower . I remember buying some lovely wine ( wolf blass ) in plastic bottles about 3 years ago , now I always transfer wine to these bottles if touring to save that bit of weight against the glass bottle + its unbreakable , Unlucky for the fella that bought wine in glass bottles the same time as I bought 6 unbreakable ones , his split the carrier bag whilst walking over the car park and smashed the glass , I know I shouldn't , but I did chuckle , oops .
So maybe reusing is your answer !