I did the same thing to my DH. I put his favourite shirt through in a colour wash and it ran with dye... The shirt was ruined but instead of admitting it I hid the shirt and snuck out the next day to try and find something that would reverse the damage. Well this bottle said you put the shirt in a bucket with so much water, and then put this magic dye reversing liquid in. So I did, and as the instructions said I left it for awhile. When I came back to it, it was much, MUCH worse. Like the shirt was so badly ruined it was just hideous. So I quietly threw it away, tied up the bin sack and put it in the wheelie bin.
DH bitched and moaned for months about this shirt, and I just kept saying I didn't know where it was, he hadn't given it to me to wash, I hadn't seen it, he must have lost it and how could he be so stupid as to lose his favourite shirt!!!
Anyway, I confessed to my evilness about 8 years later, by which time he didn't care anyway so I was totally off the hook!!!!