Easiest way to clean fatty acids out of column without cutting.

Use a piece, maybe 250cm or 500cm, of uncoated fused silica the same i.d. as your column in the inlet connected to an Ultimate Union for GC | Agilent and then to the analytical column. When the uncoated piece is contaminated, replace it with a new piece that's the same length.  It only costs you two new ferrules every time and the retention times don't change much, if at all. You can make up a number of the precolumn/retention gap pieces and have them with the ultimetal ferrule for the ultimate union already swaged on and ready to go.  

A much more complicated but automated way is to get your system setup for backflush with the necessary PSD/Aux EPC channel and a Purged Ultimate Union (PUU).  A typical setup is a 5 meter column 1 from the inlet to the PUU and a 30 meter column 2 from the PUU to the MS.  At sample injection, Column 1 flow is 1.0 ml/min and Column 2 flow is 1.2 ml/min.  After your peaks of interest have gone past the PUU but the fatty acids are still on Column 1, the system changes the flow to be Column 1 minus 3 ml/min and Column 2 still at 1.2 ml/min into the MS. Column 1 is backflushed to the injection port and the residue goes out the split vent leaving Column 1 cleaned up and ready for the next injection.   Once the hardware is installed and configured properly this concurrent backflush methodology is simple to implement.    It's also easy to replace Column 1 as you do not need to vent the MS.  

CFT Purged Union Brochure.pdf (agilent.com)

Split, Switch or Backflush - Complete guide to Capillary Flow Technology (CFT) (on24.com) Is a recorded webinar that should help.

Use a piece, maybe 250cm or 500cm, of uncoated fused silica the same i.d. as your column in the inlet connected to an Ultimate Union for GC | Agilent and then to the analytical column. When the uncoated piece is contaminated, replace it with a new piece that's the same length.  It only costs you two new ferrules every time and the retention times don't change much, if at all. You can make up a number of the precolumn/retention gap pieces and have them with the ultimetal ferrule for the ultimate union already swaged on and ready to go.  

A much more complicated but automated way is to get your system setup for backflush with the necessary PSD/Aux EPC channel and a Purged Ultimate Union (PUU).  A typical setup is a 5 meter column 1 from the inlet to the PUU and a 30 meter column 2 from the PUU to the MS.  At sample injection, Column 1 flow is 1.0 ml/min and Column 2 flow is 1.2 ml/min.  After your peaks of interest have gone past the PUU but the fatty acids are still on Column 1, the system changes the flow to be Column 1 minus 3 ml/min and Column 2 still at 1.2 ml/min into the MS. Column 1 is backflushed to the injection port and the residue goes out the split vent leaving Column 1 cleaned up and ready for the next injection.   Once the hardware is installed and configured properly this concurrent backflush methodology is simple to implement.    It's also easy to replace Column 1 as you do not need to vent the MS.  

CFT Purged Union Brochure.pdf (agilent.com)

Split, Switch or Backflush - Complete guide to Capillary Flow Technology (CFT) (on24.com) Is a recorded webinar that should help.