As happens with plastic, age has caused my pan to become brittle and it has broken in various places, including some sizeable holes.
I've tried other splash pans and I just don't like them. And I've done my best to track down someone who sells my old pan or something similar and I just haven't found it.
So about 5 years ago, I covered the whole thing with duct tape. Just made an entire shell of a pan created by duct tape. This worked pretty well, except that over the years, the tape has puckerd and gotten air behind it so it wasn't tight to the plastic itself. So as I'd scrape the pan to get out trimmings and such, I would peel up a little bit of tape and it would contaminate the clay so I couldn't recycle it and it gave me all these little spots that were hard to clean.
So I took all of the tape off so I could do a new layer. I figured every 5 years was a good amount of time between maintenance and it needed to be done.
So it took some time but I finally got all of the tape off. Then I retaped over the holes and cracks using very long strips that went over both edges of the pan. The goal was to create as few ends for my cleaning spatula to catch on as possible.
Fortunately, I had to make a trip to the hardware store for another reason before I had the chance to cover the entire pan with duct tape. While I was there, I asked on a lark if they had some sort of sprayable plastic. My goal being to create an even layer of plastic over the entire pan and tape. I figured this way I could scrape against it when cleaning and all would be good.
To my shock, they actually had such a product! It's that rubber stuff that you dip the handles of tools into. It's designed to create a nice grip on a tool handle as well as to mark your tools with a specific color so they don't go home with someone else. And they make an aerosol version of this product!
So I sprayed it over my entire pan which was partially covered in the duct tape. I found that it tended to pucker the tape edges a little bit, but then I sprayed it on thicker around those puckers and pretty much sealed them. I used the entire can for my 2 pieces of pan in about 3 layers.
After it dried (about a day), I put some of my slop over the seam of the tape and let it dry. Then I scraped part of it off with my spatula and scrubbed another portion off with just a sponge and water. It cleaned up great! And not a bit of the rubber stuff came off to contaminate the clay!!
I now have a splash pan that works really well and is easy to clean. So if you're looking for a way to extend the life of a plastic item that is hitting the brittle stage, this is a method that seems to be working for me. Just make sure you spray the stuff outside because it is a classically toxic aerosol product.