Donruss and where these came from

Back in the early 2000's as card companies were going out of business, instantly cards that no one ever heard of started to appear as that loss of companies was apparent, so was the inventory that they had hidding away.  Here is my delima,  I heard in 1990 Donruss was testing a glossy set called Donruss Aqueous Test, #'s vary from one to 5 on the cards depending on player.  But then a few months ago I saw these on ebay and they are much more rare thatn the Aqueous Test cards, but where did they come from.  They are Blue test paper cards and years vary from 1981 to 1992 and they are cut by hand and I only seen a few graded.  While the regular 1990 Donruss set is worth about $9-$15 dollars, these cards are going between $10.00 and $300.00 per card.  I hate to say that while even as the 90's cards are worth nothing, how come in took a decade to put some value back in the market.   As I will never know how these cards came to be, it would be interesting to find out just what else is going to surface.....oh yeah I do know and that is a different blog topic for a later date.