When I made my failure denim trousers, Shams suggested that I try softening them with Coke. I had not heard of this fabric treatment before. Naturally I meant to do this straight away, but having no Coke in the house (we prefer to ingest our caffiene as coffee), and no real desire to wear the jeans, it took me a while to get around to it. Here are the two denim garments suffering from excess rigidity, folded in half and placed on the table on my back verandah, hem and waist to the table. Skirt to your left, jeans on your right. Note the height of the fabric piles in comparison to the coke bottle. This is a fair dinkum experiment with evidence;)
I was not entirely sure how to proceed for the most effective softening. I bought a 2 litre bottle of coke (cheapest per mm price at the supermarker), and later found this thread at Stitchers Guild, suggesting that 2litres might be overkill.
Overkill meant that if it didn't work, it wouldn't be because of an insufficency of the product, so I placed the jeans and skirt made from my stiff denim in the laundry sink, poured in most of the Coke, topped it up with water so that all the fabric was covered with liquid, and left it to froth and bubble away for 24 hours. (The remaining coke was reserved by someone who wants to soak a dirty old coin in it)
Our laundry is under the house. Coke is attractive to insects, and fatal. Yuck.
After specific insect removal, I washed the coke soaked denim in a standard cotton wash in my front loader machine, 30 degrees C, using powdered laundry detergent, then line dried the garments (I don't own a clothes drier)
The skirt, which I have worn and washed about 10 times prior to the experiment, is noticeably softer to handle, and seems less tall when placed on the verandah in the same manner as previously. The jeans, which were only washed during the fabric storage phase, and have never been worn, feel just as stiff as previously, and do not appear noticeably shorter in this photo.
Verdict - inconclusive, but in a statistically non signficant manner due to small subject sample size, appears to work on cotton denim that has been washed on multiple occasions prior to the Coke treatment.
I would try it again if it cools down enough to wear jeans.