Karin, my friend didn't mention the discolored threads. It's good to know that it's not recommended before I actually put those oils on mine! (relief) She was talking about cracking and peeling so I was concerned...if it's not an issue then I won't want anything to get on my pearls.
And how does you friend like the new colour of the once-white silk thread
The topic has been up before but so has many topics during PG's lifespan. The conclusion last time was that's not a good idea to use any kind of oil with pearls - other than the oil that comes naturally off the skin when you wear them.
Some oils even harden and could potentially leave a layer on your pearls. Personally I wouldn't.