Wheatpaste

It has been used since antiquity for various arts and crafts such as bookbinding,[1] découpage, collage, papier-mâché, and adhering paper posters and notices to walls.

A good wheat starch paste has a strength compatible with many paper artifacts, remains reversible over time, is neither too acidic or alkaline, and is white.

[4] It is applied to the backside of paper then placed on flat surfaces, particularly concrete and metal as it does not adhere well to wood or plastic.

Cheap, rough paper such as newsprint, works well, as it can be briefly dipped in the mixture to saturate the fibres.

When hanging unauthorized billboards or signage, to reduce the danger of being caught, wheatpasters frequently work in teams or affinity groups.

Poster combo in streets of El Barrio del Carmen in Valencia , Spain
A poster adhered by wheat paste