Clean them and during the drying process the spot wicks up again but into a larger spot.
Black sticky spots on carpet.
Sticky spots something that attracts dirt got on the carpet.
One simple solution to removing tar stains from carpet is to saturate a cotton rag with water and dry cleaning solvent then blot at the affected area.
Solution first try cleaning with plain water.
You can purchase these products at discount department and home improvement stores.
This causes over 97 of recurring spots.
Sugar oil detergent grease adhesive residue such as after removing tape soft drinks urine ice melt and butter.
Mix the cleaning product of your choice with water per the product instructions in a bucket.
Wet a cotton towel with plain cold water wring it out and wipe the stain with wide sweeping strokes.
Sometimes just starts as one yarn strand of a tuft.
Look for products with ethanol alcohol to remove stubborn stains.
Whilst drying cover the spot with a moist cotton towel.
Sometimes these line up lengthwise or widthwise one instance or more and sometimes they just appear randomly.
Start as a small dark pencil eraser sized dot in the carpet.
Discolored patches may start with various shades of green or black caused by the mold colony in large number.
The moisture from the water and dry cleaning solvent should help lift the tar from the carpet fibers.
The sticky residue attracts dust and other dirt particles appearing in the form of black marks on the carpet.
However if the stain has set in you may have to repeat the process several times before you notice that the stain is fading.