Jay,
If you want to get rid of mealy bugs follow my advice. Yours is a small problem with a simple (easy) solution. I'll be more specific....
Mealy bugs reside under the top layers of the potting medium. You see them when they are active, on your plant's leaves, bulbs, etc. Isopropyl rubbing alcohol will kill them all, including eggs, but you need to contact them with the alcohol.
Go get a quart of rubbing alcohol from the grocery or drug store, and also get an empty plastic bottle with a hand sprayer. Douse your pots and plants with the alcohol, in fact, you could even fill a larger jar or pot from the kitchen and then submerge the orchid pots (only) for several minutes each....probably 5 minutes would be enough. Disturbing the top inch or less of the mix will ensure the alcohol will reach the mealies which often make an impervious shell of sorts around their nest. With the hand sprayer you could squirt alcohol into the leaf sheathes and other cracks and crannies, etc.
It would be a good idea, although not entirely necessary with most species, to rinse your pots after treatment, with plain water, this will prevent any chance of damage to the roots. Also, tip out any alcohol that remains in or on the leaves.
You do not need to use Orthene with only a few plants. As I said, Orthene is a very mild pesticide, it carries the same warning label as a bottle of aspirin, isopropyl alcohol, and numerous other household items. It stinks, but it's cheap and it works very well if you read and follow label directions...
I'm an expert orchid grower and you can trust my advice.