I did searches for this and didn’t find anyone mentioning this, so here goes:
I almost never use a tool to get a part up, either with ABS or PLA.
Here’s what I do:
I print a skirt around the part, usually about 4 mm away and one layer high.
After the part is printed and the bed has cooled to around 40-50 degrees C, I apply isopropyl alcohol between the part and the skirt, all the way around the part, with an eyedropper. I apply as much as possible without overflowing outside of the skirt. The alcohol makes a nice meniscus where it touches the base of the part. Then I wait a bit.
The alcohol seems to pull itself under the part, through surface tension I guess. For a 4-cm or so circular column, for example, after five minutes or less I can usually simply lift it off of the bed. If not, a fresh application of alcohol and another similar wait, and up it comes. No prying, no stress on the PEI.
Usually the skirt ring comes up easily, after that. I use the leftover alcohol sitting on the PEI by wiping it around with a paper towel to clean the PEI, since it’s OK to use it for that anyhow.
It works somewhat better for ABS, since it doesn’t seem to stick as well as PLA, but it works well for both.
Example: Late last night I had an ABS part of about that size firmly stuck onto the bed, and didn’t have time to do any of that, so I just left it overnight as it was. When I got up in the morning it was still firmly stuck, and the bed was now at room temperature. I applied the alcohol, and within 10 seconds or so I started hearing the cracking sound of the part breaking itself free. Another 10 seconds or so passed, and I lifted the part off of the bed without resistance. The entire bottom was wetted by the alcohol, it had quickly crept into the space between the bed and the part.
I hope this helps!
– Mike