The struggling motor manufacturer ­General Motors is auctioning off hundreds of classic and speciality cars to save storage costs at its heritage centre in Michigan.

Nearly 100 collectable vehicles will go on the block in Florida this week including a 1920 Chevrolet Model T truck from the early days of mass produced vehicles. Also up for sale is a 1999 Chevrolet Camaro used in the movie Runaway Bride, starring Richard Gere and Julia Roberts.

The company has raised more than $9m this year by slimming down its fleet of ­speciality vehicles which includes prototype "concept" cars once intended to wow crowds at car shows around the world. Among those already sold included a 1998 Cadillac outfitted as a "Popemobile"‚ for the late pope John Paul II.

Greg Wallace, manager of the General Motors Heritage Centre, said: "We've seen an opportunity to clean up some of our storage and maintenance costs."

Any extra cash will help shore up GM's ailing finances. The company's new chief executive, Fritz Henderson, has warned that GM may yet have to declare bankruptcy if it is unable to reach a deal with its bondholders and unions that satisfies the Obama administration.

GM has been cutting its costs down to the bone. The firm, which owns brands including Vauxhall, Saab and Hummer, has shed more than 60,000 jobs over the past three years. Savings have gone down to details such as switching off lifts and escalators at its headquarters in Detroit.

Wallace said the initiative to sell ­speciality cars pre-dates GM's present financial difficulties: "The corporate problems came along pretty much after we decided to do most of this."

Those up for disposal, he said, were vehicles with no business case, were no longer being used or were duplicates.

Elsewhere, the loyalty of President Obama's staff to the US car industry has come under the microscope. A survey by the website Politico found that only five out of 23 cars parked on the White House's West Executive Drive, were American.

Japanese cars appear to be popular among members of Obama's auto task force. The head of the president's National Economic Council, Larry Summers, drives a Mazda and economic adviser Austan Goolsbee has a Toyota. Budget chief Peter Orszag owns a Honda and a Swedish-made Volvo.

Obama himself has a US-made Ford Escape hybrid, although he rarely uses it because it is parked in Chicago.