I claim the ornamental design for the cosmetic bag with a removable liner, as shown and described.
FIG. 1 is an exploded, perspective view of the cosmetic bag with a removable liner;
FIG. 2 is a perspective view of the cosmetic bag with the removable liner inserted therein;
FIG. 3 is a fragmented, sectional view of the cosmetic bag with removable liner inserted and an integrated, interior lip-flap positioned to secure the liner; and,
FIG. 4 is a side, cross sectional view of the cosmetic bag with a removable liner taken along line 4-4 of FIG. 2.
The broken lines showing a bag are for the purposes of illustrating environment and form no part of the claimed design.