as plastic goes, well white out as you know for rear release.
As a general rule of thumb white/green are usually used on pins with approx 22 guage or lighter wire in them, they are small and sharp, often with red/blue twisted pair databus wires or a airinc 429 buss wiring.
RED, 20/22 guage wiring, good on those airbus stubby pins found around in light assy's and I think I remember them in some mod blocks too. This is a guage for analogue logic or low amp supply.
BLUE, 16/18 guage often in high vibe/weather exposure areas, definately some potential for some juice here.
YELLOW, 14 guage, not as common and high amperage.
Now getting into a well equipped daniels kit with front release, tweeser apps etc. Might be worth pulling out the books.
Another thing, I hate the metal throw away tools, I have learned from my elders experience that iso alcohol wooks wonders in lubricating connectors (if you can get your hands on DEOX it is great) but not everyone wants to pay to supply it.