Reusable filter systems and frames, methods of assembling and transporting the same, and uses thereof

A reusable filter system for a interchangeable pleated filter, comprising: (a) a reusable frame, comprising a first, second, third and fourth holders; (b) at least one flexible sheet, configured to attach to at least a portion of the upper pleat tip face and/or lower pleat tip face and to extend outward from the first pleated edge and the second pleated edge; and (c) at least one spline, wherein the first, second, third and fourth holders are configured to be reversibly connected with each other to form the reusable frame, and wherein each of the first, second, third and fourth holders further comprises a spline receiving portion sized and shaped to receive the spline.