Here is the recommendation from Trex live chat:

"Sap stains are very aggressive stains and there's no guarantee for removal. However, you can try this procedure in an attempt to minimize the stain:

Remove the sap from the boards ASAP. The sooner the better. In an inconspicuous area, test Goo Gone or mineral spirits with very light scrubbing and check for discoloration. If no discoloration, apply the Goo Gone or mineral spirits with very light scrubbing to the sap and/or stain. Warning - heavy scrubbing will cause discoloration of the boards.

If large enough droplets: Chip off as much as possible with a putty knife or a razor being extremely careful not to cut the decking. Place ice in a sealed bag and place over sap area. Leave on for 10-20 minutes. Remove and chip remainder of sap off of decking surface. In an inconspicuous area, test Goo Gone or mineral spirits with very light scrubbing and check for discoloration. If no discoloration, apply the Goo Gone or mineral spirits with very light scrubbing to the sap and/or stain. Warning - heavy scrubbing will cause discoloration of the boards."

Well it still beats treating a wood deck every other year.

Asked them what soap to use, BTW. (The website info just says "warm, soapy water.") They said to use 1/4 C dish (or laundry) soap to 1 gallon of water. I personally would hesitate before using that much laundry soap though.

Here is a recommendation from a long time Trex customer. Live with it. I got more stains from all kinds of crap. Power wash or scrub with Oxy to kill the the moss and live with the rest.I love the stuff. And no, I don't work for the manufacturer. No splinters,splitting and always comfortable to walk barefoot on.

We have the same issue. Let me know if you are successful with the sap removal we are just starting to try different methods.

In my living room hardwood floors and my kitchen floor when i get tree sap i use murphys oil soap. Let it sit for 20 minutes and it comes right off. Considered trying it on my deck but i dont want an oily stain. I may try tbe ice idea but it may be too late because the sun has it baked in.

We tried power washing on low with a a recommended Kurd litter for decks. No luck. We ended up getting the tree cut down and figures that we will have to live with it. It's been on the deck all winter now, so not sticky. This sap trouble happened right after we put up a 25k timber tech deck. Timber tech also recommended murphy's oil soap and simple green, then gently scraping. Maybe I didn't leave it on long enough. Last summer I mopped the whole deck with it, then with warm water. Nothing worked so far. So disgusted. At least it's not sticky so we can use the deck this summer

I, too, have struggled with pine tar on my deck. What I do is spray the spots with Go Gone, then let set for 5-10 minutes. Then scrap with plastic putty knife and then clean up with light brushing with soap and water. Have tried nail polish but found that this discolors the deck.

Try using Corte-Clean is a Composite Cleaner made especially to clean composite decking.

I saw no mention in Corte-Clean's web page nor a QA feature to verify if it works removing sap. Please post verification.

I guess not many people have decks under trees which can get sap all over the deck. You can call the company and ask them or you can spend $40 dollars and try it... If it works you can use it all the time, if it doesn't work you can use it to clean the rest of the deck and it will remove everything else except sap.

That being said, there are not many products out there to clean Composites, so if everything else failed it's worth a try.

Try hand sanitizer.......works on our composites and our cars

Yes hand sanitizer works somewhat, but not on the stubborn stuff.

We ended up cutting down the tree. It was either the tree or the brand new deck! Sap was no longer sticky after the first winter.

I don't have a tree over my Trex deck but I did build a pergola with PT lumber and had a few drops of sap - I wiped it up quickly and when it dried it left a white discolouration. I first tried warm soapy water and a brush but that didn't work so I tried WD40 and a rubbing alcohol rinse - came right off.

What proportion of WD40 to rubbing alcohol did you use?

The person who said to live with it is exactly correct.

We have a 680-sqft composite deck and we purposely built it around a 40-ft Norway pine. We were managing sap removal fairly well until the summer of 2021 when pretty much the entire deck got covered, and I mean covered, in sap. Couldn't find even 1 square foot without sap on it. Never seen anything like it. Even our Hannamint furniture took a beating.

So we cut the tree down a few weeks ago.

We have tried Goo Gone, soapy water, power washing, composite deck cleaner, scrubbing, rubbing, scraping.

With the density of the droplets from 2021 we are ending up smearing the sap so instead of a million little white sap stains, now the sap is essentially pressed into the fine groves in the deck mold...so a broader white spot appears. So, it's either live with the small white spots or live with the remnants of the rubbing. Neither is ideal.

We are simply going to give it a washing with the Krud Cutter deck and fencc cleaner to remove the surface stickiness and live with a white spotted deck.

That is, until I call to have someone come and rplace 100% of the boards. That's the only way to get a totally sap free deck for us, is to replace it all.

I use rubbing alcohol. Seems to remove most of sap, but leaves bit of shine which I think is the sap diluted.