We sent 3 gel filtration columns, one in pretty bad shape. They had gaps in the matrix, dehydrated and had high pressure. ReGenFix managed to regenerate all of them and bring them as new. They provided calibration curves and column tests proving the columns were regenerated. We also performed calibration on our own HPLC system and it matched their calibration. Their customer service is also excellent and are very responsive by emails. I would recommend reviving your old columns with them instead of letting it sit in the corner of your lab for years or throwing them out. You'll get a pleasant surprise that you can use your column again after thinking it's not possible to regenerate. Also, the whole process, including shipping, took 2 weeks!