HP 950 printhead is relatively easy to maintain and clean. We composed three methods which can solve most of the clogs.
Let's start with HP's built-in function. The HP's built-in function can be very effective if you know how it works. HP has three levels of cleaning. At the first level, HP will wipe the printhead clean. If the print is undesirable and you selected "continue", the printer will move to second and third cleaning level. At these levels, the printer will inflate and deflate an air bladder inside the cartridge. Ink will be squeezed out the cartridge and thus push clogs out of printhead.
To remove stubborn clogs, you can combine and alternate the levels of cleaning. Do not do too many cleanings in a row. You may flood the ink pad underneath. The excessive ink may form new clogs and make things worse. Give a little time for the clogs to soften and then run the cleaning after few hours.
The rest of the methods requires more efforts. If you are interested, you can read it here: https://www.bchtechnologies.com/blog/how-to-clean-hp-950-933-printhead-officejet-8600-8610-8100-8620