vacuum pump oil

[star882]

If I use a compressor as a vacuum pump (filled with mineral oil) on a system filled with POE, is there a problem with some POE entering the vacuum pump and causing sludging? Is it too little to worry about? Is it usually solved by changing the oil after every use?
Note that the system will use R134a so it must use POE. POE is not an option for the vacuum pump due to its moisture sensitivity.

[Xeon th MG Pony]

I used an Old strainer as an oil sep, drilled out the capillary and threaded in a small machine bolt, after a run simply undo the bolt to drain the oil. This way nothing gets into the compressor.