Dyeing silk

Has anyone out there tried to dye a delicate silk garment? As you may remember from previous queries from me, I had to store clothes, etc. in a damp garage while work went ahead on our home, and as a result was left with various problems e.g. pervasive damp smells, damp shoes, etc. With the help of you all I have overcome most of these but I do have a lovely, delicate nightdress (never worn, bought by DH whose opinion of my size was optimistic to say the least!). I can't get the stain left by the damp out of the fabric, and I'm thinking of dyeing it, but don't know if this would be a mistake. It's stupid really, I don't want to get rid of this lovely feminine nightdress even if I have never been able to wear it for over 30 years! Any ideas, please?