David MacAskill, from Eaglesham, has stored the payment made out to Roy Stirling for more than four years.
Mr MacAskill, who owned a arts and craft kiosk in Princes Square for 18 years, met Mr Stirling when he sold the Big Issue on Buchanan Street. After Mr Stirling received a cheque for £2100 from the Scottish Prison Service (SPS) over a claim, he asked Mr MacAskill to keep it for him. However, Mr MacAskill, 67, was not able to return the cheque and is urging him or someone from his family to come forward.
Mr MacAskill, who retired in April 2010, said: "I knew Roy because he used to come into Princes Square while he was selling the Big Issue for a chat or to use the toilet."
In September 2009 Mr Stirling received the letter from solicitor firm Robertson and Ross in Paisley. Enclosed was a payment from the SPS for £2100 which he was awarded over a slopping out claim.
Mr MacAskill said: "Roy said he didn't have a bank account and he was living in hostels. So we signed the envelope and I have held it on to it.
"I haven't seen him since then and now I'm retired I won't see him. I just want him to have it."
Mr MacAskill has been carrying out inquiries at the solicitor's firm, the Big Issue and other agencies.
But he has not been able to find out where Mr Stirling is.
Mr MacAskill said: "I have no idea what's happened to him. The Big Issue were very helpful but they didn't know where he is."
Big Issue editor Paul McNamee said: "Roy Stirling is not badged-up at the moment, and as he is not on The Big Issue's registration system we don't have any details for him. This is a kind act from Mr MacAskill. If Roy makes contact with us, we put him in touch with Mr MacAskill."
Anyone with information is asked to contact the Evening Times on 0141 302 7000 and details will be passed on to Mr MacAskill.