How many "empty" bottles of Soft Soap does it take to make a full bottle?

Answer: 16.

On 8/24/2011 the fourteen-month experiment completed with the sixteenth "empty" bottle of Soft Soap being dumped in, topping off the bottle. Here's what the final conglomeration of at least a half-dozen different flavors of Soft Soap looked like:

Yes, all this soap came from 16 Soft Soap bottles from which no more soap could be pumped out!

Data Analysis

• This particular bottle claims to hold 8.5 fl. oz.
• It took 16 "empties" to fill it, thus...
• Each "empty" bottle of soap contains approximately 0.53 fl. oz. of wasted soap.
• The newer-style bottles actually contain 7.5 fl. oz. of soap, thus...
• Approximately 7% of the soap in these bottles it typically wasted.
• The list price for these is about $2.50 per bottle, thus...
• Each bottle wastes approximately 17.5 cents.
• Our company used about 14 bottles in a year, thus...
• We would have wasted about $2.45 had I not recaptured it!
• Final conclusion: I wasted far more time running this experiment than can possibly be recovered by soap conservation (that wasn't the goal, but is amusing to point out).

Data, Notes and Photos

Here is the calendar of soap usage. Our company was growing over this time period, so our soap use definitely accelerates:

Here's what the bottle looked like as the 13th bottle is nearly emptied on 6/17/11:

Here's the bottle on 5/20/11, after 10 empties had been dumped in.

Here's the stock market price of Colgate-Palmolive in the past year. I expect this experiment has, and will continue to have, an effect on this graph.