[greenyes] PET question

[KirbGood@no.address]

This question was received through the CWC.org web site.
Any PET specialists out there with the answer?
Please reply to him at the address following the email.
Thanks.

Dear Mr Matt Morrison,
  I am very thankful for all of your information, we have in Colombia a 
company who believe in the benefits of recycling, we started working with some 
companies that collect materials for recycling, teaching them how to clean the 
best the pet bottles, we also have invest in an equipment for sheet extrusion, 
and started with a new concept of recycling, which it is to give a very good 
product to the market.
 Since we start this project we have been improving our quality, must of this 
job it is because your excellent information in best practices in PET 
recycling, and for that thank you very much.
 But I still have a problem with the material, we have some black spots that 
present into sheet and we are doing what you suggest, and it is to filtering 
with fine mesh at the extruder, but the screen get cover of this black very 
soon so we are having a high consumption of screen, at the screen it is look like 
burn material or carbon, we have completely sure that it is not contamination 
with PET, because we use only soda bottles.
 Please can you help us giving some information of the origin of this, we 
have use Post industrial, and it has this but in less, bur when we work with post 
consumer it increase.
 It can help if you tell us also where do we can find more information.
Thank you again for all your help that you give to the industry and cleaning 
this world
Best regards
Alejandro Betancourt
Bogotá Colombia
ABetancourt@no.address