The pants are connected to Scotland’s most famous UFO incident which was subject to a police probe.
Paranormal investigator Malcolm Robinson said he offered to donate the “iconic” trews worn by believer Bob Taylor but was turned down.
Late forestry worker Bob reputedly saw mysterious dome-shaped objects land in a clearing at Dechmont Woods, West Lothian, in 1979.
According to the teetotal churchgoer, metal spikes then dropped down and attached themselves to his trouers.
He later woke in dishevelled state before going to cops.
Baffled investigators were unable to establish what caused unusual marks seen on the ground.
Detectives bagged up Bob’s torn trousers as they probed whether he had been assaulted.
They were later given to the British UFO Research Association before being passed to Mr Robinson.
Respected war hero Bob continued to maintain he had been attacked by a “spaceship thing” until his death aged 88 in 2007.
And Mr. Robinson hopes evidence of the mysterious episode can be preserved for future generations — despite museum chiefs’ reluctance.
He insisted: “This is not any old pair of trousers.
“They are part of Scotland’s biggest ever UFO story.
“A full-blown police investigation was carried out including a forensic examination of the ripped trousers.
“It might sound bizarre to some. But this is an iconic piece of Scottish history which rightly deserves it place in a museum.”
Mr Robinson said he has taken the trousers on exhibition tours and claimed to have turned down cash offers for them.
He explained: “I’ve been offered thousands of pounds by an American businessman but I have refused.
“I wanted to donate these trousers to the National Museums of Scotland. Sadly, they refused. I’m very disappointed.”
Bob said officials had apologized via email and said they “already had similar material”.
A National Museums Scotland spokesman last night said this was a mistake but explained: “We are offered objects as donations to the National Collection all the time.
“We don’t have space or capacity to accept them all.”
Source: The Scottish Sun