Those were also in a horrible condition. These are looking pretty good for a trainer manufactured in 1991. The plastic has not cracked too much although there are a few cracks here and there. They are a black/purple colour with a leather/nubuck type upper and some sort of plastic/rubber sole.
I did want to clean them up but had fears that I may end up doing something I would regret. The item "1991 CONVERSE AERO GLIDE BASKETBALL SHOES TRAINERS VINTAGE EXTREMELY RARE UK 9" is in sale since Friday, April 12, 2019. This item is in the category "Clothes, Shoes & Accessories\Men\Men's Shoes\Trainers". The seller is "afshar156" and is located in Beckenham, Kent. This item can be shipped to United Kingdom, Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Australia, United States, Bahrain, Canada, Japan, New Zealand, Hong Kong, Norway, Malaysia, Singapore, South Korea, Switzerland, Taiwan, Thailand, Bangladesh, Belize, Bermuda, Bolivia, Barbados, Brunei darussalam, Cayman islands, Dominica, Egypt, Guernsey, Gibraltar, Guadeloupe, Grenada, French guiana, Iceland, Jersey, Jordan, Cambodia, Saint kitts and nevis, Saint lucia, Liechtenstein, Sri lanka, Macao, Monaco, Maldives, Montserrat, Martinique, Nicaragua, Oman, Pakistan, Paraguay, Reunion, Turks and caicos islands, Aruba, Saudi arabia, South africa, United arab emirates, Ukraine, Chile, Bahamas, Colombia, Costa rica, Dominican republic, Guatemala, Honduras, Jamaica, Kuwait, Panama, Philippines, Qatar, El salvador, Trinidad and tobago, Uruguay, Russian federation.