The yellow are a small amount of hardened paint around the lid (see pictures).
Holbein Artists' Gouache Paint Set 12 x 5ml Tubes For Illustration Design
Holbein Artists Gouache Paint Set 18 x 5ml Colour Mixing Painting
Holbein Artists' Gouache Paint Set Extra Fine Pigment 15ml 24 Tubes Painting
Holbein Acryla Gouache Paint Set Acrylic 20ml 12 Pack For Artists
Holbein Acryla Gouache Paint Set Acrylic 12ml 5 Tubes Intro Colours
Holbein Acryla Gouache Paint Acrylic Resin 20ml Tube Ivory White
