|Remember to use only the best adhesives for your collages. Rubber cement or white household glue is not recomended since neither is archival. Rubber cement will turn brown and eventually papers will loosen. Glue sticks are good but no matter what adhesive you’re using, make sure it has an archival label.Acrylic mediums are an excellent adhesive for collage since they will protect your work from deterioration and also from contact with other materials that might not be acid free. Items that are not acid free can migrate to other papers in your collage and damage them. Sealing each item in acrylic medium , whether it be gloss or matte is the best practice since you never know if an item is completely acid free. I’ve used a spray by Krylon called Make it Acid Free that could be tried for additional protection. Acrylic mediums are applied with a synthetic bristle brush and are water soluble when wet. However they’re polymer based and form a permenent plastic coating when dry. In a workshop I took with Jonathon Talbot, he coated the front and back of the support pieces with acrylic medium before he began. Always do both sides or the support will warp. Mediums come in gloss or matte so experiment with each to see which one you prefer !