Horray! I'm reluctant to recommend fire right off the bat because I don't want people to burn themselves, but it certainly seems to be effective.

Update: Hi, We have now done this 5 times (about twice a year). The filastruder still works just fine with the repeated burning off of all the plastic at high temperature.

So yes, i can confirm that, very high temperature cleaning using fire , (till the plastic vaporises) is a Very very effective method of cleaning the contamination and clogs from the filastruder,  making it almost Like New again.

The key to avoid material deformation is to let it cool slowly and don't hit it on anything.

Metal deforms easily when glowing hot. Hold gently, carefully, Don't squeeze it hard.

We let it sit vertically on some stone / brick outdoors on concrete and torch it with a blowtorch with a soup can cut in half into a "C" shape to retain the flame and heat within . Like a mini furnace.

Don't breathe in fumes. Don't position yourself downwind.

Happy extruding.

steel
stainless steel
brass

So you should be good up until around 800C.

I'm pretty new here, so not sure if I should start a new thread or not. However, I am interested in this topic. I have access to a furnace (with vent line) and am wondering if that could be used to clean out the Filastruder? Perhaps set at 500 deg or so? I'm worried about the metal softening, but I have used this method in the past to clean out stainless steel machine parts.

I am working with some funky polymers (and blends of polymers, which are finicky) and may end up with burned and/or stuck material inside the hotend. Cleaning with fire (heat) is way easier than solvent-based methods.

2./ A ready-made compound that is specifically mixed for a specific purpose: these compounds come in the shape of ready to use pellets and can be made very potent to remove difficult polymer-residues or notoriously stubborn colours. The product usually foams and maker can even decide to mix fibreglass into the compound to make it more effective. This may be less universal than the Par 1./ solution in a filastruder environment. Plastics processing plants usually work withing a limited range of polymer grades and these may prefer a tailored purging compound.

As mentioned our own filastruder is not yet delivered so I am not yet able to check if the set of rules used in the Plastic Industry also apply to the filastruder but I am determined to find that out for you - I've also received some kind messages from individual community members offering to test on their equipment and that might be a intermediate solution, provided said memebers would be willing to share their findings and recommendations.

This is going to be very interesting

I am totally new to the forum and in fact still waiting for our own filastruder to arrive, so please excuse me if this information has been posted before: I notice a lot of people having trouble cleaning between batches and/or colour changeovers: In an industrial environment dies and other parts are cleaned in a furnace by pyrolysis (= simply HEAT) but it is a very, very controlled environment. Torching clogged parts may seem be a solution to remove residue but to me it looks like really wild and  uncontrolled.

Even if industrial extruder components can be cleaned by pyrolisys, operators tend to avoid this because it complicates matters and one ends up with burned residue which has to be removed anyway. Using a purging compound is the best solution to remove pollution and to clean out the barrel/screw and die between colour or product change-overs and also as a regular maintenance habit to keep things clean and shiny.

I have seen posts that mention the use of ready made so-called purging compounds which  are offered on ebay and the likes but these products are usually too weak to do anything more than to keep a clean barrel clean for a little longer. What you people probably need is a real industrial purging/cleaning compound: one that lightly foams up once it is inside the barrel: that feature, combined with its ability to rub off residue and polish the internals is what is going to make your life easier.

We use several types of these compounds on Industrial extruders: some are universal type and are to be mixed in small quantities into the polymer granules that you are using whilst other types have been specially mixed for a specific application. When our filastruder will be up and running we intend to try the different types of compounds and will report on the outcome to the forum.

Being friendly with our supplier, we might even persuade them to make a "special brew" for filastruder use and he may even be persuaded to supply the product in small quantities especially for filastruder use - These outfits traditionally only sell by the pallet-load to the plastic industry and that's probably why this type of product has not yet been discovered by private users.

Would the community be interested in our findings?

Massive interest. This would make my extrusion life easier, PM sent.

Torching clogged parts may seem be a solution to remove residue but to me it looks like really wild and  uncontrolled.

Welcome to the bleeding/burning edge of 3D printing technology.

It seems that a lot of lab scale extruders can be split in half along the long axis to allow access to the screw and facilitate cleaning.  I don't see us having that ability anytime soon with out a lot cost.

This is why I stay with ABS, put the nozzle in butter container with some solvent and the barrel with some paper towels soaked in acetone.

Even if industrial extruder components can be cleaned by pyrolisys, operators tend to avoid this because it complicates matters and one ends up with burned residue which has to be removed anyway. Using a purging compound is the best solution to remove pollution and to clean out the barrel/screw and die between colour or product change-overs and also as a regular maintenance habit to keep things clean and shiny.

I have seen posts that mention the use of ready made so-called purging compounds which  are offered on ebay and the likes but these products are usually too weak to do anything more than to keep a clean barrel clean for a little longer. What you people probably need is a real industrial purging/cleaning compound: one that lightly foams up once it is inside the barrel: that feature, combined with its ability to rub off residue and polish the internals is what is going to make your life easier.

We use several types of these compounds on Industrial extruders: some are universal type and are to be mixed in small quantities into the polymer granules that you are using whilst other types have been specially mixed for a specific application. When our filastruder will be up and running we intend to try the different types of compounds and will report on the outcome to the forum.

Being friendly with our supplier, we might even persuade them to make a "special brew" for filastruder use and he may even be persuaded to supply the product in small quantities especially for filastruder use - These outfits traditionally only sell by the pallet-load to the plastic industry and that's probably why this type of product has not yet been discovered by private users.

Would the community be interested in our findings?

good posts just remember everyone's setups are different and its always gonna be about what works best for you.
kind of the fun of it is figuring that out.

I think it's an important discussion because in an other posting you make the comment that because of these issues you rather use pre-colored pellets but as [elmoret] pointed out the price for those is higher then the uncolored material and if the carrier was to blame it's important to know.