Sorry, web site needs picture up-loads and more words but I got tired of it and haven't finished it out.
Idle jet holders have idle jets that slip into the hollow screw portion of the holder. Pull jets out look through them toward bright light. If blocked then blow air through jets from the end with the split legs. Then look through the idle jet toward the sky or bright light to visually see they are clear. This is it for the idle jets. If car was running OK then suddenly began to have low speed running issues then blocked idle jets is most probable issue.
It would be good to review the info regarding "Air Filters and Intake Manifolds" on my web page:
Performance Oriented Also, follow the link in that discussion to the "Advanced Procedures" web page entitled "Improving Sealing Efficiency Of Air Cleaner Housings" for more info regarding debris in your carbs.
I summarized the two above in the info on this web page:
http://www.performanceoriented.com/troubleshooting/ entitled "Sources of Debris in Float Wells".