Salon colourists mixing tint or bleach for client services, and home colourists doing box-dye or root touch-ups who want a proper mixing tool instead of stirring with the tint brush itself.

A tint brush alone tends to leave unmixed streaks of colour or bleach powder clinging to the bottom and sides of the bowl; a flat spatula gets into those corners and folds the formula over on itself in a way a brush bristle can't, so the colour-to-developer ratio ends up more even across the whole batch. That consistency matters most with bleach, where an unmixed pocket of powder can process unevenly on hair.

Pour developer and colour or bleach powder into the mixing bowl, then use the flat end of the spatula to fold and press the mixture against the sides of the bowl, working out lumps or unmixed powder until the formula reaches an even, pourable consistency. Use the spatula's edge to scrape down the bowl's sides so nothing is left unmixed, then switch to a tint brush to apply the finished formula. Rinse the spatula right after use, before colour dries on the plastic.

Pro: chemical-resistant plastic won't corrode or discolour from repeated contact with peroxide- and ammonia-based colour, unlike some metal utensils. Pro: small size fits standard tint bowls without splashing product over the rim. Con: it's a mixing aid, not an application brush, so a separate tint brush is still needed to apply the colour to hair. Con: being lightweight plastic, it can crack if used to break up hard bleach powder or pry at stiff product rather than just stirring.