Polypropylene Bed Adhesion I recently upgraded to a Polypropylene print bed, but I haven't actually been able to complete a print. 

Adhesion seems incredibly inconsistent, even on the same spot. Sometimes it goes down great, and sometimes it just curls up and clumps on the nozzle. I even cranked the temp up to 220&nbsp;&deg;C for the PLA and 70&nbsp;&deg;C for the bed in an effort to get it to stick for an initial layer, and it still isn't sticking. 

Any tips? I've been cleaning with rubbing alcohol, but I don't know if there's any trick. Clean when hot? Cold? Let sit after cleaning before using? Is it just a matter of incredibly precise bed leveling?
If you are using PLA, 200 for the extruder sticks the best for me.  The other issue with adhesion is the greater the difference between the extruder temperature and the bed the poorer adhesion. There are other things can help with this.  Using a higher bed temperature for the first layer can help.  A slower extrusion speed allows the extrusion to cool more before getting as long of a length to for the contraction force; thus improving adhesion.