I just posted the following on the PC and related searches thread in response to chloroform searches. However, I believe it also belongs here because, IMHO, it provides an explanation as to when the car was cleaned, why it was cleaned, and how chloroform may have ended up in the trunk.
George and Cindy drive to the tow yard to retrieve the Pontiac. It is important to remember that neither at that point in time have any idea whatsoever that Caylee is missing. They simply believe Casey has been preventing them from seeing her.
George opens the car door and smells what he believes is human decomposition (and we later learn he was correct.) Mr. Burch smells it too.
George is obviously worried it might be Caylee or even Casey. He asks Mr. Burch to go to the trunk with him. They open the trunk and there is no body, but there is a bag of trash with flies and maggots on it. Mr. Burch says that must be the source of the smell and tosses the bag. George never inspects the garbage to make sure there was a pizza in it - why should he?
IMHO, it is quite reasonable for George to temporarily accept this alternate explanation for the smell because he is not aware that Caylee is missing.
Progressing with the sequence of events, George drives the car home, puts it in the garage, and disconnects the battery just in case his daughter shows up and tries to drive it away. Cindy comments on the smell being that of something dead. George says there was a bag of garbage in the trunk with a pizza in it and that the bag had maggots and flies on it. Cindy asks if it was the pizza and George says it was. Again, a reminder that to this point neither knows Caylee is missing.
I can imagine George then saying a few things about how irresponsible Casey had become to abandon a perfectly good vehicle, never tell her parents about it, and on top of all that leave a bag of rotting garbage in the trunk while the car sat in the hot Florida sun for two weeks.
The two try to air out the car while it is parked in the garage, and I believe they try to clean it. First they spray the bugs in the trunk with pesticide, which may have been manufactured with chloroform as a solvent. Then they vacuum out the dead bugs and other debris. They try to clean the stain in the trunk, which they believe came from the trash bag. They may have used their portable steam cleaner to do this. They may have used dry cleaning fluid to do this which, by the way, has chloroform as an ingredient.
Cindy cleans out the interior, seeing Casey's slacks, noticing the smell, and tossing them in the wash. Remember, they are trying to clean a stinking car their daughter abandoned and they had to "bail out" for several hundred dollars. They still do not have any clue Caylee is missing.
Cindy texts Casey, gets a response, texts her back, gets another response. No idea what was in that exchange. George takes off for work.
Cindy continues going through the car and runs across Amy's resume. Apparently Cindy's text exchange earlier with Casey did not satisfy the question(s) she had, so she calls Amy and asks her to take her to Casey.
During the ride over Cindy complains about Casey. IIRC it ran the gamut of her stealing, lying, not letting them see Casey. They arrive at Tony's, get Casey, and drive back to Ric's to drop Amy off.
Now Cindy wants some answers. She is angry and confused, and Casey is not giving her a story that makes sense. They drive to a police station, and from the parking lot Cindy makes the first 911 call. She also calls George. George calls Lee and asks him to head over to their house to help Cindy get to the bottom of whatever is going on. Cindy drives back to the home with Casey - Lee is already there.
Cindy makes a second 911 call. Continues trying to talk to Casey and get some answers. George heads home from work. Cindy leaves the room and Lee tries talking to her. It is then that Casey mentions the kidnapping story which Cindy overhears. She rushes in, gets more information from Casey, and goes into a panic. I submit that this is the point where Cindy first puts two and two together.
She calls 911 again, this time mentioning the car smell and missing baby, and George happens to walk in on the call.
I do not view their cleaning of the call earlier as anything but innocent given they were not working with all the facts. If they hid the fact they cleaned the car in later LE interviews, that is obstruction. But the act itself was not.