I also saved two liter pop (soda for you'all in the south) bottles. Used a 1 3/8" step drill to drill multiple holes in sides and ends, then removed cap. Then took a knife and slit a 4" long slice in the side (not connecting with any of the previous drilled holes. Through this "slot" I could stuff a 2 or 3" rock through and the rock will not come out and is also big enough it will not come out any of the drilled holes. Then at the edge of the bank, give a calculated toss into desired water depth, and presto, you have recycled small fish habitat, FHM or whatever wishes to enjoy.
The bottles are visible until enough algae grows on them, then they are hardly noticeable.
Gator-Aide bottles work good also and they are more substantial than the pop bottles. Other bottles would work also.
I started doing this, with no good way to weight them. Put gravel in them and if they landed wrong, the gravel would run out the holes. The holes are needed for water flow. Don't want stagnant water in there or no fish will use it. Then I thought about the slot method. Larger rock goes in but does not come back out. Worked great. Step drill
These things are invaluable for drilling holes in plastic pipe, etc. for making fish habitat. Get one if you need big holes through thin stuff.