Another suggestion... (if using Pot. Ox Dev) .... try leaving the print in the developer for 5+mins.
The longer time spent in the developer has always helped facilitate better and more efficient clearing for me in every instance and all the diff papers I've worked with, especially the more difficult to clear papers.
Also, another combo for the clearing baths that works well for me.
1st bath: Citric Acid mixed into some hot water (bunch per gallon)
2nd and 3rd baths (basically HCA recipe) A bunch of Sodium Sulfite and a bit of Sodium Metabisulfite per gallon of hot water.