What do you hold on to after foster child leaves?

I regretted that I didn't think about this before my girls left. But, I do think God was thinking about it. My friends helped me pack clothes and bedding and such. Then the week after, I packed and delivered all of their remaining toys/clothes. I happened upon on two separate instances their blankees. See, when they came, I got them both toddler sized soft blankees for daycare. #1 had outgrown hers over the winter and I got her a larger one. She still did carry the first one in conjunction with the second one. #2 "lost" her first blankee at daycare, so I had gotten a replacement. The daycare later found the first one. I mysteriously found her blankee under my pillows after they left. #1 did not ask for her blankee when I took the toys over. I chose to keep it. It isn't like I can actually smell them on it, although, I think that there is some part that my brain does process. But, having their blankees tucked under my pillows brings me comfort. And they brought me great comfort the first few weeks when I had them cuddled up in my arms at night. Tears are streaming down my face now as I type this. Of course, I have found the missed clothing item, or socks. Yesterday, I was straightening the side of the fridge, and realized that I had papers that they had colored still there. And of course I have pictures here and at work. The one that hit me hard was finding a left behind stuffy. I did not consciously decide to keep something of theirs, but now, I feel that I will double blankee the next kids so that I might keep a blankee of theirs too. I cant bring myself to even wash the blankees. So, I wonder, do you purposely keep a memento, outside of the standard photos and such, to remember your foster child?