Object Class: Euclid
So this isn't a Euclid SCP. According to what you've written, this SCP can not compel people to put it on, nor wrap itself around people. This is quite simply an inanimate object that only activates when worn. As such, it can be thrown in a locked box and left alone. As such, this would be a Safe class SCP. Given the general tone of the article, I feel as though you were hesitant to use "Safe" because you wanted to convey that this is a very dangerous anomaly. But keep in mind that there are Safe class anomalies that can and will kill people consistently, and that this is only referring to containment difficulty.
Item SCP-3211 is to be contained in a 30 cm. x 30 cm. x 12 cm. airtight glass container at a minimum temperature of 8 degrees Celsius.
The exact dimensions, composition and temperature of the container are completely unnecessary. There is nothing in the description regarding your SCP's interactions with temperature so, since we can assume that temperature does not make your SCP any harder or difficult to contain, this is unnecessary. This logic is also applied to the dimensions(containment does not become more difficult in a 31 cm x 30 x 12 cm box) and composition(a steel box will not cause a containment breach). Remember, the Foundation optimizes. If a simple box is all that is necessary, then it will not go through the extra trouble of installing heat modulators and refining dimensions.
Bacterial scans for ringworm or any parasitic disease are required on a weekly basis
The presence of bacteria does not make your SCP any more difficult to contain. I'm a little confused as to why there is such a fixation in the containment procedures about the hygiene of this object. At the very least, this is another redundancy issue since ease of containment does not change with bacterial presence and/or we can assume the Foundation will maintain the SCP properly. At the very worst, this is a red herring: I was fully expecting there to be something about ringworm or bacteria somewhere along the way and was rather confused and disappointed when I found there was not.
any addition of white stripes on the red surface must be reported immediately to an overseeing supervisor.
This is one part of the issue with the white lines. I will address this later.
When cleaning item SCP-3211, a minimum of three (3) D-class personal are required to enter the holding cell and check SCP-3211 for parasitic bacteria and any new markings or stripes. Two D-class personnel must stretch and hold out SCP-3211 while the third D-class individual checks the conditions required to keep SCP-3211 clean.
So the same hygiene arguments I made above reappear here. This sounds like ridiculous paranoia on the Foundation's part. Try to tailor your special containment procedures to the special abilities of your SCP. If your SCP changed when dirtied, then cleaning it would be acceptable but you would, even then, need to perform some literary gymnastics to justify this.
However, I believe I see where you are coming from with this passage. This is very similar to the cleaning procedures for SCP-173's containment cell. However, there are differences. For 173, one person going in alone would result in death during a blink. Two people would have one person focused on mopping and another staring but death could still occur once the latter individual blinked. Three people ensure someone can focus entirely on mopping while the other two stare and keep 173 locked in place.
In your case, the difference between 3 people cleaning this(2 holders 1 brusher) is not justified to be better than 2 people(1 holder and 1 brusher), which itself is not justified more than a washing machine. If you want to keep these, then keep in mind that you are going to have to associate an extreme risk to being alone with your SCP, being alone with someone else and the SCP, and not cleaning your SCP at all.
Also, I recommend avoiding the "number(x)" formatting. It's typically reserved for pill dosage instructions. I would just stick to one or the other since, regardless, this formatting causes the reader to pause their reading just for a moment before continuing on.
Under no circumstances can any personnel wrap SCP-3211 around their waste, or knot into a fashion commonly used in Brazilian Jiu Jitsu.
'Waist' is spelled incorrectly. You should replace 'or knot' with 'and tie it into a knot.' Now, this thing about tying the belt into a fashion only found in Brazilian Jiu Jitsu confused me a little. Out of curiosity, I looked up what this knot looked like and saw that it looks almost exactly like the knot I used to tie for Aikido. I think it would be better to just say "martial arts knot." This topic will be revisited in the concept check at the end.
unless approved by an overseeing council member.
I assume this is talking about an O5 Council Member. I don't think your SCP has warranted their attention as it is right now. A senior researcher is fine, maybe even one accompanied by a security party. However, a council member is a stretch of disbelief many readers will not attempt to make.