I believe it is a law in most states if not all that crematoriums must be cleaned after each person. I have heard of crematoriums being involved in lawsuits over that very problem. Hope this helps.

While everything various province to province and state to state, I can tell you that the VAST majority of Cremains are NOT only your relative. There is almost guaranteed to be trace amounts of the last person in the oven mixed in with your loved ones remains. To properly clean out an oven takes an extremely long period of time. Most Crematoriums will only thoroughly clean out their ovens a few times a month. In a very large city like New York where Crematoriums are running almost 24/7, it just isn’t feasible to clean them out after every person. For the most part, once a body is consumed, it is still largely bone. These cremains are quite literally dragged out of the oven using what looks like a Hoe with a sharp angle on it. The oven also contains a groove about an inch deep all the way through the middle of the floor, which is also dragged out with a similar instrument. The Cremains are then collected and put in a grinder to get the “Ash” that people are used to. As such, there almost certainly will be trace amounts of other people in with these ashes. I personally have never heard of a Funeral Home/Crematorium being sued for this, though there have been quite a few sued for mislabeling an Ash package.

The authorization forms for most crematories contain disclaimers stating that there may be small degree of comingling that is inadvertent.

they do. but there is no way they can get all of one persons ashes completely out. i'm sure it's hard to get all those ashes out of there, think about when your dusting your house, a lot of dust is left when you're through. that's how you could possibly get part of another person mixed with your ashes.

A little ash mixing never hurt anybody, especially dead people who have already been totally incinerated. In a poetic way it almost meets the 5 second rule.