Beauty care product

A method for coloring and/or bleaching hair, comprising the steps of:

• (a) providing a first product comprising:
• a sealable plastic container comprising a base section, a body section, and a neck section forming an aperture;
• said sections delimiting an inner reservoir;
• a sealing means, affixed onto the neck section of the container;
• a developer component, contained within the reservoir of the container;
• wherein the reservoir comprises upon storage no more than about 70% of the component by total volume of the reservoir, the remaining volume being filled with gas;
• wherein the body section is four-paneled and comprises a non-collapsible squeezable front panel, two symmetrical collapsible side panels and a non-collapsible squeezable back panel;
• wherein the ratio of the average thicknesses between front and/or back panels and the side panels is at least 2:1;
• (b) providing an additional product being a packaged component selected from a tint component comprising at least one primary precursor, a component comprising at least one secondary precursor, or combination thereof,
• (c) pouring the additional product into the reservoir remaining volume of the container of the first product;
• (d) mixing the developer component homogeneously with the additional product
• (e) applying the mixed composition onto hair.