Yes, I have a number of tokens, gift certificates and passes and they no longer have purchasing power anywhere. Their value has become zero.

While I originally kind of liked, "time credits" I don't think they work as was proven recently by the co-op bargaining lots of the poor in Argentina which was discussed on the blog. Such appears to work at first, and the intentions might be good, but then things go bad.

The other kinds of scripts also don't work, because they are subject to counterfeiting and the same troubles the fiat money printing of The Fed let loose on the U.S. Dollar, and Not everyone who participates will be honest. It's the money that has to be honest, not the participants.

An, "hours unit" besides being backed by nothing like most goberment authorative issuers, is subject to widely changing wage rates or goberment imposed wage rates which would dilute the value of any savings, among other bad outcomes the same as with the U.S. Dollar today.

The currencies made with real metal content (N. Dakota Indian silver dollars for one example among others) would overcome these obstacles and they seem to be perceived as a threat by TPTB which is why the makers are often taken to court over the matter or jailed. There's several recent examples of this.

A partial excerpt and a solution from the article, We Don’t Need No Stinkin’ Gold Standard:

What we need is market-produced money. This may take a number of possible forms, such as e-money backed by metals such as silver and gold, or silver coin, or gold coin and bullion for larger transactions.

Market-produced money differs radically from government-controlled and government-produced money. With market-produced money, there cannot be a systematically injurious deflation or harmful shortage of money. If the demand for money exceeds the supply to the point where the costs of a money shortage to demanders are exceeding the costs of producing more money, the market will produce more money and eliminate the shortage.

By the same token, with market-produced money, there cannot be a systematically injurious inflation or excess of money. If the supply of a money exceeds its demand at a given price, the market will reduce the supply and demanders will seek alternative money, thereby eliminating the excess demand.

With market-produced money, variations in the demand and supply of money will be of no greater consequence than the analogous variations of any other of the thousands of goods and services that the government does not control and whose prices are market-determined.

With market-produced money, there cannot be a money-caused business cycle of any substantial consequence, because prolonged alterations in money supply and interest rates caused by government control of money will be absent…

It's not Just the short supply that creates the value of the chocolate in a POW camp, it's the work it takes to produce the item, combined with the demand (which includes the quality) and the ability to purchase, along with the short supply.

A person may have to compete for goods and services too. For instance, would you want a handful of precious metal coins to work hard a whole day, or would you want a bucketful of stale tobacco and melted stale chocolate that the seller swore up and down he thought was fresh and tastie (or was the good kind of inhaler, the label even says so) when it turned out otherwise?

If a person has the option and can buy what he wants with the coins (and like jadalina, knows where to get what they want) the person who offers him the coins would get the service or the good and the person offering tobacco and chocolate might have to go without.

Justin Case said, "As far as scripts and credits go, it depends on your local community.  If you are among half a dozen households in an area that get along well, for example, you probably help each other out and have no formal way of tracking each others' contributions (i.e., "you help me fix my car and I help you fix your plumbing")."

I've seen that setup of, "you help me and I'll help you" just fall apart badly way too many times, even between best of neighbors and friends or relatives in a good economy. The car wasn't "fixed" as good as expected, or the plumbing needs an extra five unanticipated hours of work at midnight that wasn't calculated into the deal. Or, they'll say, "I did X and now they won't do Y" at all, or not until next month when you don't need it. And the slightly famous line which goes something like, "That will be the last time I work for peanuts."
 Stuff like that makes scripts and credits a bad bargain for people on both sides of the trade in many cases and it's why many people won't risk their relationship by trading in such a manner as they value their relationship more.
 I'm sure it works ok for some people some of the time, just not all of the people all of the time and certainly not all that often between strangers, enough to depend on anyway. That all seems like Socialism and Communism and it's often not very equitable.

Some groups of people such as the Amish might do this, but I imagine even they have difficulties, I suspect it's their religious views that are the bond and not the credit or script. Or perhaps they don't do this and their barn raisings and such are a form of charity with no strings attached?

Justin Case said, "But it works only if everyone remains honest and is committed to the purpose of the script — a way to reconcile the value of goods and services contributed and needed.  An hour of time is valued in terms of pounds of food, for example, and could be independent of what the hour or food is worth in dollars."

That's just it, the idea of people being committed to a script (or fiat dollar) is slightly ludicrous on the surface (think about it, committed to a script?) and if the value of one or the other is not fixed, it fluctuates. I don't imagine many people want to knowingly work for a fluctuating value unless it works out in their favor and even then someone else is getting the short end of the stick.
 The story Ferfal relates to on his blog (or was it in his book?) about the little old man who everyone thought highly of yet he turned out to be the criminal shows that even the best of people won't be honest, that's why the money has to be honest. There's an endless list of people not being honest when it comes to money, in good times and especially in bad times, and surprisingly sometimes over petty things.
 
An hour of time is valued in potatoes today and beets tomorrow because the potatoes spoiled last night? Are they mostly rotten, or just somewhat rotten, knowingly or not? It's an ever changing system based on food not being spoiled and such – which isn't a very stable way to trade – yet it might work for a short term trade between neighbors, relatives or friends, but even then, or should I say, even now, those kinds of arrangements sometimes fall apart and create all kinds of strife by themselves and grow beyond that initial trouble, something that a sound reliable money based on something like metals would lessen considerably.

That Canadian goberment attitude above is scary stuff, by the way. The breakdown of the rule of law and all that.