Never painted polo,

but painted plenty of plastic kits, first, they must be washed with dish soap and warm water. After drying, handle them with latex gloves, I prime with enamel, used to use Walmart’s colorpace gray, they stopped making it, you could use flat black or get comparable flat gray primer. Then I used cheap craft store acrylics, no problems. I’ve used brushes, make up sponges and thinned down and airbrushed some. Depends on type of siding on kit. Also, I have used spray enamels, mostly on clapboard siding kits.

I think the most common problem with painting plastic

is the failure to wash the parts thoroughly with soap and water before painting.  The plastic molding process requires the use of mold release to get the parts out of the molds after they have cured.  The manufacturers typically don't worry about cleaning the mold release off of the parts before packaging.  

Mike is right in the advice he gave you.  It is just that since you can't see or feel the mold release, many people don't realize it is there, and it acts as a paint release if not cleaned off.

Guys, it’s POLA, not Polo!

LOL

Peter

Pola not Polo

Oh! Like the shirts then.

Marco?

Marco!