There are a variety of reasons a rug might “bleed” on you. Let’s go through different scenarios for a wool rug like this one, where the red dyes have migrated into the neighboring off-white areas:
What could create this type of dye migration? Several things.
FUGITIVE DYES – if the red is shown to not be colorfast during your dye test, it could bleed from improper exposure to water from a flood or a poor cleaning attempt. Your dye testing process will show you this potential risk, and you can determine what dye stabilizing solution to use and which shampoo.
EXCESS DYE or OVER-DYED APPLICATIONS – if the rug has never been cleaned before, there might be a bit of “excess” dye in the fibers that may wash out on the 1st cleaning, just as with a new colorful shirt in the laundry. Or, if additional color has been ADDED after the rug was woven to make it brighter (or to make it look older, such as with a tea-wash antiquing application) this additional dye or ink could bleed during a cleaning.
With excess dye, using the proper dye stabilizing solution you can protect the neighboring areas to keep the transfer of the “extra” dye from landing on the wrong areas – it just washes away in the bath.
With over-dye applications, especially inks like India Ink, you cannot protect the neighboring areas so you need to identify these rugs before cleaning to avert a disaster. Often these rugs crock color with a dry towel alone, and transfer a sizable amount of color with the dye test itself, so know when you need to turn down cleaning. Dye stabilizers work on DYES not inks.
HIGH HEAT or HIGH ALKALINITY – a colorfast dye may bleed even with the proper application of a dye stabilizing solution IF it is improperly combined with high temperature during cleaning or high alkaline cleaning solutions (such as traffic lane cleaners). If you plan to clean the rug outside of recommended pH and temperature ranges, then always test the dye with that temperature/alkalinity to make sure you do not create dye damage.
PAST IN-HOME CLEANING OF RUGS – the biggest problem with having a rug cleaned in your home using wall-to-wall carpet cleaning equipment and solutions (or a home-owner Bissell or Rug Doctor) is the amount of residue left behind in the fibers after the “cleaning.” This chemical residue buildup tends to be on the alkaline side, and over time can affect the acid dyes of especially wool rugs and can create a “bleeder” out of these rugs. It might clean up fine one or two times in the home, and on the third the dyes may bleed all over and you have no idea why. It’s because of the extended build-up of all of the residue NOT removed in the past.
If you have a rug of any value at all – never clean it in the home. Natural fiber rugs are meant to be washed.
REPEAT PET STAINS – pet urine starts off as an acidic stain, and then turns alkaline over weeks and months. If it is not cleaned up right away off of a rug this will create long term permanent dye damage that devalues your rug. A rug may have colorfast dyes, but all of the areas with urine exposure will bleed no matter what steps are taken to stop that. This is why pet urine is the most dangerous “spill” on rugs, and why you need to jump on cleaning it up as soon as you see the puddles especially if you have valuable rugs.
The more time you take to inspect the rug before the cleaning begins, the more problems you can avoid.