He rushes up a side alley and returns with a basket of shiny white bracelets and pendants, all made from elephant tusks. "This is what you are looking for, I think."
The international ivory trade was banned in 1990 to protect elephant populations ravaged by poachers taking tusks for jewelry and ornaments. But conservationists warned that the unregulated markets of Khartoum, Sudan's capital, and Omdurman on the other side of the Nile River had developed into a hub for the illegal trade.
Now it seems Sudan has acted. The government recently warned traders that they must get rid of their ivory or face prosecution.
The decision to act against the ivory trade signals the Sudanese government's interest in showing that it is ready to abide by international law.
Joseph Malwal Dong, Sudan's minister for tourism, says action on the issue was overdue.
Some say government involved
After decades of conflict and famine, Sudan's government has moved toward a peace deal with southern rebels and claims to be working to end fighting in the western region of Darfur, where tens of thousands have died and millions have fled to refugee camps since fighting erupted in 2003.
"We have all wanted to do this to protect species that are in trouble," Dong says. "But the country has been torn apart by war, making it difficult at times to keep law and order.
"Now that we have peace in the south, we can do some of these things that we could not do before."
The most recent available figures for Sudan's elephant population, provided by Care for the Wild International, suggest that it declined from 133,000 animals in 1976 to 40,000 in 1992.
Overall, Africa's elephant population was cut in half between 1979 and 1989, largely as the result of poaching, Care for the Wild says. Elephant populations have recovered in some southern African nations since 1990, when the Convention on International Trade in Endangered Species banned the international ivory trade.
Wildlife trade expert Esmond Martin surveyed Khartoum earlier this year for Care for the Wild International. Martin found that the amount of ivory on sale had grown since a previous survey in 1997. In all, he counted more than 11,000 items in 50 souvenir shops.
"I was very surprised. While markets were disappearing in other parts of Africa, the market here had gone up," he says.
"What also surprised me was the number of traders who told me the government was involved in transporting the ivory, offering it for sale to some of the shopkeepers in Khartoum and Omdurman."
The survey found that ivory prices had doubled in Sudan during the past eight years as demand increased and world supply decreased. In 1997, a kilogram (2.2 pounds) of unworked ivory cost $45. Today the price is $105.
Some of the raw ivory is destined for carvers in Cairo or Asia, Martin says. Shopkeepers told him the ivory was mainly from Congo and southern Sudan, with small amounts from Kenya and Chad. He concluded that much of the growth in the ivory trade was a result of the recent arrival of Chinese workers in Sudan.
"They are working in the oil industry, construction of bridges and some factories. There are several thousand, minimum," Martin says.
"There is not a lot to do at night in Khartoum, and all the shops are open until nine or 10 at night, so there is a lot of shopping. The Chinese are not just buying one or two pieces but are buying many ... and may be selling them in China."
He says that demand for ivory remains high in East Asia and that, because of insufficient checks at Sudan's ports and airports, it's fairly easy to smuggle small items out.
Martin says news that the Sudanese authorities had moved to stop the illegal ivory trade, if true, "is exactly what we wanted to hear. We must now hope that this is enough to end this trade."
'I have five children in school'
Today, licensed shopkeepers are allowed to sell only items carved from ivory culled before the ban was imposed.
In the shop next door to Musa's, Mohamed Altib drags a bulging plastic bag from beneath his cluttered desk. It holds carved ivory masks, crocodile-shaped ornaments and candlesticks.
"People who work or trade in ivory got a visit about 2½ months ago from government officers who told us to take it all off the shelves," Altib says. "After three months, they said they would be back to take all the ivory and give us money in return."
He says he has 200 pounds of raw, unworked ivory and about as much in carved items. Altib estimates the raw ivory alone is worth $20,000.
"It was a good trade. I made a lot of money from the ivory," he says.
"I understand that this comes from an animal and it is important that we do not finish the elephants, but I have five children in school and university, and I am going to lose a lot of money because of this."