If you are someone that has realized "just vacuuming" or "just dabbing with a mild soap solution" isn't a complete answer as to how one may safely deep clean their custom blinds or shades, we can help. There are safe ways to clean custom window treatments using a variety of methods. We've briefly outlined some basic information to get help get you started and to hopefully avoid an expensive disaster!
Before determining which cleaning methods may be appropriate for the type of blinds or shades that you have it is critical to know a little bit about their construction. Spend a few moments looking at the window treatment, noting what types of materials are present in their construction. Those made of synthetic materials (polyester fabric, nylon cords, aluminum, plastic or vinyl vanes or slats etc.) are easier to clean than those that have parts made of natural fibers or materials (wood slats, cotton fabric, cords or tapes). How old are these blinds? Environmental factors like the sun (UV radiation, heat, sun fading) humidity (warping, shrinkage, mildew) and age (weakened glues or adhesives, brittle plastics or dry rotted cording) also must be considered. No cleaning process will not resolve issues caused by age or wear and in some cases may create more problems.
Blinds with slats of metal, synthetic materials like vinyl or plastic composites and synthetic cords can be cleaned with soap and water. Depending upon the type of finish and the degree of grime involved the actual methods will vary. Hand cleaning or ultrasonic cleaning methods are appropriate.
For real wood blinds wiping with a damp cloth and treatment (on natural finished woods) with a fine wood oil afterward is best. If wood blinds are really filthy some professional blind cleaners will literally disassemble the blind, clean the slats by hand and ultrasonic or wash the cords separately (so they don't damage the wood with immersion in water which cracks the finish etc.) before putting the blind back together again. If someone says they ultrasonically clean wood blinds - no matter what their technique (immersion in water will allow for swelling of the wood and damage to the finish - even if it is minimal) there will be damage to the finish or paint when the wood swells as it absorbs water on the cut ends, route holes or potentially anywhere else.
Fabric shades are not all created equal! Hunter Douglas, Bali, Graber and a few other fabricators of custom blinds list some recommendations for the cleaning for their blinds in their materials, though in some cases this information is incomplete. Shades of polyester fabrics with glues that won't be affected by water (in older shades glue lines weaken depending upon the UV exposure, age and type of glue used) can be washed in water using an appropriate hand method, ultrasonically cleaned or cleaned with an injection/extraction (On-Site) cleaning method. Knowing how to handle the shade is important as is getting it dry quickly.
Generally speaking, if you have a room darkening shade with papery type fabric or a metallic liner inside the cells then water is NOT good for your shade. An injection/extraction cleaning method using a dry cleaning solvent (done by a professional) is a safer option than any water based methods (Wet cleaning voids warranties in these types of Hunter Douglas shades). Ultrasonic energy also damaged some types of foil, so a knowledgeable blind cleaner adjusts their procedures and methods appropriately while a novice may inadvertently damage the shade.
Vertical blinds with vanes made of vinyl are easily washed in water with a mild soap. Using a strong detergent or degreaser may remove some finishes or colors on some of the painted patterned vinyls. Hand cleaning or ultrasonic cleaning methods are appropriate, however if the vanes are old and brittle they may split or crack when handled for cleaning.
Vertical blinds with fabric vanes can often be wet cleaned (however even some synthetic fabrics will shrink slightly), though natural fabrics or those with sizing in the fabric often will shrink and ripple or curl at the edges if wet cleaned. Dry cleaning solvent won't affect the sizing in the fabric or cause other adverse issues that wet cleaning methods may create. Some environmental shrinkage of the the fabric in many "groovers" (fabric inserted in vinyl channel panel) may exist before any cleaning occurs - it often goes unnoticed.
Vertical blinds that have a fabric insert with a vinyl back require careful examination before cleaning. Over time the clear plastic edges of 
the channel panel tend to darken to yellow, amber or finally a darker brown color as a result of long term exposure to UV light or aging. Typically the darker the discoloration the more brittle and less flexible the vanes are, making cleaning them without damage a risky, if not an impossible task. The fabric insert also needs to be inspected by flipping it out of the vane at the bottom and looking for any backing. Often the fabric is a woven polyester (or blend of fibers) with no backing made of washable synthetics, so wet cleaning is a good option. If you see a paperboard backing or plastic liner then dry cleaning with an injection/extraction (On-Site) method is the safest method as water may not be compatible with existing adhesives or cause the paperboard liner to swell and deform.
Roman Shades are done using either wet or dry cleaning methods depending upon which solvent is appropriate for the type of fabric or other components used in the shade's construction. If you don't know what the fabric is and don't have the fabricator's endorsement for wet cleaning then a dry cleaning method is the best option. Plastic parts, cord guides or loops on the back of the shade often become brittle with age and may need replacing if they should break - so be sure the cleaner is prepared for such possibilities.
Silhouette, Nantucket, Shangri-La and similar sheer fabric shades in many cases can be wet cleaned, however using the wrong cleaning method for the room darkening version of these shades or poor cleaning procedures or techniques can lead to ruined, puckered or damaged shades. While the sun will sun rot the sheer backing on older shades the most common problem with cleaning these shades is poor cleaning techniques that leave puckers, water lines or other issues that knowledgeable professional cleaners know how to avoid. Dry cleaning (dry solvent instead of water based) is the recommended method for most room darkening versions of these shades as wet cleaning damages the adhesives used in the construction of the layers in the fabric vanes.
Luminettes, Vertiglides, Slide-Vue, Verticells and other other specialty shade products can often be deep cleaned by a professional. Home owners are not typically properly equipped or wise to assume the liability for these cleaning projects. Find a qualified professional blind cleaner to do the work. If you would like assistance, use the links on this site to request the services of a local professional blind cleaner.