So what about something like:

* US charity that recycles US-hotel used soap

* The recycled soap is resold in US as a charitable item

* Profits from recycled soap sales are used to help fund/grow 3rd world soap manufacturers, or to help them lower the cost to make it, or subsidise the cost to more available to citizens of their country

I see your point and, I know it seems a little roundabout, but could this solve the issue?