Make very functional parts storage from plastic already in the recycle bin. Plastic Orange Juice bottles work great. Also Cat Litter pour containers (jugs) work well. Containers with a side handle work best. Using clear plastic is great because you can see much of what's in the container without having to dig or pour it all out.
Step 1: Remove Labels
First, remove labels from your given bottle. I already had removed the lable - so you don't get to see that picture... I remove labels by scraping up a corner with my fingernail. Then, once about a quarter inch is up, I S-L-O-W-L-Y pull the label off. In my experience, maintining about a 90 degree angle between the bottle and the pulled up section works well. Usually a sticky glue residue will be left behind. I have found spray silicone lubricant (WD-40) works great. Just spray it on and let it soak the area with the glue residue for a couple minutes - maybe not that long. Then wipe off and it looks wunderbar.
Step 2: Cut Off the Top
After removing the label, carefully cut the top off. You could use a utility knife (be REALLY careful) - i speak from experience on this. Better yet you could use one of those hot knife cutters. I don't have one of those but looks like it work really great. You could use a saw. I used my compound miter saw. When cutting take time to survey the design of the bottle. You want to still have a structurally sound bottle after the cut. Balance out your desire for large opening with the need for leaving material around the top of the handle. In the picture, you can see what my bottle looks like before and after the cut.
Step 3: Smooth the Lip
With the top cut off, you will likely have a rough ege around the rim. I use sandpaper to smooth it out. If you have a particulary jagged area, you can use scissors to trim areas. With the chop saw, I usually get a nice straight cut - so I'm able to avoid the scissor trick. When sanding the edge, be careful to only sand on that edge area, or else you will scratch up your soon to be beautiful container.
Step 4: Finish the Lip
The last step is to refine the lip. The sandpaper did a nice job, but it can be better with fire or heat. I use an inexpensive butane lighter to melt just the edge of the bottle lip. Go all the way around. While the plastic is warm, you can reshape the edge to your liking. Now your edge will transclucent and smooth and less "scratched". Also wash and dry your container and you are good to go.
I do not recommend using a heat gun.
Step 5: Caution
A word about safety. When using the butane lighter, use common sense and avoid flammable substances especially fumes. Working outside is usually even better than working in a "well-ventilated" space. You may be releasing toxic chemicals when heating and most certainly when burning plastic. Really, it's not good for you. I don't know if it's cancer or three-headed babies, but it's not good for you. When, I melt or bend plastic I ususally wear a full Haz-Mat Suit. Unfortunately, today - mine was at the drycleaners. Be careful out there.
Baby Ruth anyone?