Step 1
Talk to General Bentnoze or Wartface in Goblin Village.
Search crates for 3 goblin mail.
Follow instructions for making dyes.
Dye one goblin mail blue and one orange.
Talk to Generals again.

Items needed: 3 Goblin Mail, Orange Dye, Blue Dye.

Enter the goblin village and talk to either General Bentnoze (red goblin) or General Wartface (green goblin). You hear their conflict about which armour colour is the best for celebrating the new goblin century. Suggest to pick an armour colour for them. They want you to bring a new colour of goblin armour to them. Search the crates around the village and you should find 1-3 sets of goblin mail. Alternatively, kill the goblins and they will eventually drop it.

Now you need to make a blue, red and yellow dye. The instructions are detailed below.

1. Red dye requires 3 redberries. Collect these next to the mining area south east of Varrock.
2. Yellow dye requires 2 onions. Collect these out the front of Melzar's maze, north of Rimmington, or from behind farmer Fred's house north of Lumbridge.
3. Blue dye requires 2 woad leaves. Purchase these from Wyson the Gardener in Falador park. You may buy each leaf individually for 15gp, but if you offer 20gp, he will give you two leaves (which is a much better deal).
4. Once you have these ingredients, go to Aggie in Draynor Village. Ask her to make you a red, yellow and blue dye (this costs 5gp each time). Use the yellow dye on the red dye to turn it orange.

Alternatively you can buy the dye. Use the orange dye on one of the pieces of goblin armour, and the blue dye on the other. Return to Goblin Village. When you bring the newly coloured goblin mail, they will have a goblin named Grubfoot try it on. When Grubfoot models the orange armour in a cut-scene, the Generals say they don't like it, and they ask you to deliver a blue goblin mail.

Speak to them again and the goblin generals will have Grubfoot try on the blue armour. Once more they decide that they don't like the new colour. They ask you to bring a brown goblin mail, which is the original armour colour.This can be found by searching crates in the village. Speak to the Generals one last time and they will be satisfied with the brown goblin mail and will give you reward.