Particles found in Hayabusa sample chamber -- could be plain old Earth dust

According to the news article below, they've found some particles in the Hayabusa sample chamber, even though it hasn't been opened up all the way yet. One of the scientists doubts that the particles are asteroidal or extra-terrestrial.

Japanese lab finds 'minute particles' in asteroid pod

The first part I don't get is that the sample chamber hasn't been opened completely. How does that work? Did they just crack the lid and look under it?

Quote: "We have started the opening process of the sample container of Hayabusa since June 24, 2010 and confirmed there are minute particles,"

"started the opening process" is somewhat like being halfway pregnant. Either the chamber is open or it isn't, right?

Further: "Researchers have not fully opened the capsule yet but have found more than 10 specks visible to the naked eye, said another JAXA scientist, Toshifumi Mukai. Mukai conceded these particles may not have come from the asteroid. "I have a feeling that they are not cosmic dust," he said, adding that it was also possible that they were from deep space."

And then it says: "When Hayabusa was launched in 2003, the canister was open, meaning it may contain materials that originated on Earth, a JAXA spokesman said."

It was OPEN? How do you expect to collect material from an asteroid when you fly the sample chamber when it's OPEN? I sure don't get that.

We'll just have to see what they say next!!!