Cleaning our plastic

We really need to put down some sort of standards or processes for cleaning our plastic for re-use.

We shredded our first batch Thursday of HDPE and PET in a semi commercial shredder.

I can tell you one thing the scrap plastic STINKS! I mean it smells extremely bad and many containers were used for household cleaning products, so there was a bit of a toxic brew in there.

I have seen some conveyors running plastic thru a tank of water with some lye that cleans the plastic and rids the paper labels.

Then it is rinsed.

It looks like there is a bit of work to be done to improve our capabilities to really recycle and process large amounts of plastic, as running 50 kilos a day just will not cut it, if we are to make a impact.


Slow and steady wins the race I guess. Washing on a big scale does seem to be a big challenge.

If the plastics aren’t cleaned properly do they not bond/melt properly?

Can you mix HDPE and PET?

My workshop gets all its plastic from community member drop-offs, and I require people to bring me clean plastic and then I cut out labels that can’t be peeled off. I’m in a area where people are invested in recycling, so it has been pretty easy to make sure the plastic people bring me is clean. I have a motto “Dirty plastic is trash” and that helps people get stuff clean.

If you can get a washing machine, you can also do a very fine mesh bag full of flakes in a front load washing machine. I find I don’t necessarily need to do that for my products, but you may for certain high detail parts.

I have at the moment an Ibc about one third full of water with a pool chlorine tablet in it. This over doses the water and cleans the plastic just by soaking it. I also strip shred my milk bottles for the washing process, easier to handle, clean, and dry.  I tried soaps and disinfectants, chlorine seems to be the cheapest and the longest lasting. So far I’ve cleaned about 5 months of plastic milk bottles still good. At the end I plan on filtering the water through a sand filter and reusing.

has anyone tried shredding the plastic before cleaning it? i haven’t tried it, but i would like to try shredding it and then putting it in an agitation tank with water and cleaning solution, something adapted from a washing machine… i have seen people build machines like this for other purposes

I was thinking ocean salt water (to clean & get labels off) & then a one rinse of some kind, before the chop. Since most the bottles are collecting along shorelines & fresh water is limited world wide. But still there will need to be a sludge pond for all this washing residue.

no you can not mix the two. Water contamination makes the plastic foam up. that is how EPS is made.

I got 17 kilos of HDPE yesterday. It is contaminated with dirt. I have soaked the red pieces (coke bottle caps) in water and a local bleach that has a soap in it. It is kinda clean but something better needs to be done.

I need to process roughly 30 kilos of plastic daily into usable products to earn a living.

At this point I am thinking it will be better to purchase from a processor.