So it sounds like you have critters on your plants
These instructions work well for scale, mealy bugs or mites.
Washing the plant off when you water will help, especially if you put a few drops of dishwashing liquid (like Blue Dawn) in the water and drench the pot at the same time, but you will probably need to use insecticide to completely get rid of the problem. Also, check your bloom and bud spikes. Insects like to hide in the flower segments and also under the nodules on the spikes. Peeling back the dry sheath on cattleya bulbs will often reveal hidden colonies. Cutting the spikes now may help eliminate the problem faster.
Regardless of what insecticide you use it is important to treat the effected plants thoroughly. Use a rag or an old toothbrush to remove any insects that you can see; clean the plants; treat the tops and bottoms of leaves; and drench the pots with insecticide or soap. Insects like mealy bugs can live happily for years in the potting media or under the lips of your pots so this step in very important. An initial spray of Isopropyl Alcohol can kill insects on contact but will not have a lasting effect and should be followed up with the proper insecticide.
It is also important to repeat once a week for at least three weeks, because all insecticides do not kill all insects at all life stages (eggs, young, and mature).
Finally, alternating insecticides, especially when you are using insecticides that are not as strong, insures that insects do not become resistant.
If you can put your plants outside or close them off in a greenhouse for a few days until the odor goes away, we suggest Orthene wettable powder (2 teaspoons per gallon) for scale, mealybugs, aphids or whitefly on the tougher orchids Like Cattleyas, Phalaenopsis, Cymbidiums, and many Oncidiums. Otherwise, we also sell Safer's Insecticidal Soap, and Bayer "Advanced Garden" Rose and Flower Insect Killer. You alternate among those. For mites you must select a miticide that is labeled to kill mites.
As with all chemicals, take precautions such as the following:
* Use in a well ventilated area and avoid breathing chemicals.
* Wear gloves to protect your skin. If contact occurs wash thoroughly with soap and cold (not warm) water.
* Avoid being around the plants until spray residue as dried on the plants, usually a minimum of 4-6 hours though some pesticides require 12-24 hours.