Interesting question! I do soak my babies about once a year, but I soak in a bucket of clean, RO water or distilled water. I like to do a thorough cleaning out of the salts built up. I leave each one in for about 30 minutes. I use a fresh bucket of water for each plant. (I borrow containers from friends so I can do multiple plants at a time) I put them in just deep enough to cover the pot, and tuck in wild roots if I can without damage. About every 8 to 10 watering I use plan water to help keep buildup down. I also clean my orchid's leaves 3 or 4 times a year, with a mild Physan solution and a very soft toothbrush. Clean off the dust, water spots, old papery sheath coverings, etc. (both sides of the leaves) And that gives me a good opportunity to look thoroughly at each plant for any signs of problems.
I have never thought about soaking in a fertilizer solution. I'll be very interested to hear what others have to say.