The ornamental design for a disposable petwastecollector, as shown and described.
FIG. 1 is a first perspective view of a disposable pet waste collector showing my new design;
FIG. 2 is a second perspective view thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a rear elevational view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof;
FIG. 9 shows the disposable pet waste collector in an in-use configuration; and,
FIG. 10 is an exploded perspective view of the disposable pet waste collector in which the disposable pet waste collector is in a disassembled condition.