Contrast the sleek and clean lines of a modern minimalist kitchen with a vintage sign collection. Look for signs with simple designs and muted colors to maintain the minimalist aesthetic. Hang the signs on a white or neutral-colored wall to create a focal point in the kitchen. Pair the signs with stainless steel appliances, glossy cabinets, and minimalistic furniture to achieve a harmonious balance between old and new. The vintage signs will add a touch of nostalgia and warmth to the minimalist space.