diff --git a/src/interface.rs b/src/interface.rs
index 317d7ce2..617a259b 100644
--- a/src/interface.rs
+++ b/src/interface.rs
@@ -176,10 +176,6 @@ pub fn set_mathml(mathml_str: impl AsRef<str>) -> Result<String> {
     static MATHJAX_V2: LazyLock<Regex> = LazyLock::new(|| Regex::new(r#"class *= *['"]MJX-.*?['"]"#).unwrap());
     static MATHJAX_V3: LazyLock<Regex> = LazyLock::new(|| Regex::new(r#"class *= *['"]data-mjx-.*?['"]"#).unwrap());
 
-    // Strip out processing instructions and comments -- these are not MathML and can cause DOS problems in the parser
-    static PROCESSING_INSTRUCTION: LazyLock<Regex> = LazyLock::new(|| Regex::new(r#"<\?[\s\S]{1,2048}\?>"#).unwrap());
-    static XML_COMMENT: LazyLock<Regex> = LazyLock::new(|| Regex::new(r#"(?s)"#).unwrap());
-
     // These have some length limits to avoid DOS attacks via long strings
     static NAMESPACE_DECL: LazyLock<Regex> = LazyLock::new(|| Regex::new(r#"xmlns:[[:alpha:]]{1,32}"#).unwrap());
     static PREFIX: LazyLock<Regex> = LazyLock::new(|| Regex::new(r#"(</?)[[:alpha:]]{1,32}:"#).unwrap());
@@ -204,10 +200,8 @@ pub fn set_mathml(mathml_str: impl AsRef<str>) -> Result<String> {
 
             let mut error_message = "".to_string(); // can't return a result inside the replace_all, so we do this hack of setting the message and then returning the error
                                                                      
-            let mathml_str = XML_COMMENT.replace_all(mathml_str, "");
-            let mathml_str = PROCESSING_INSTRUCTION.replace_all(&mathml_str, "");
             // FIX: need to deal with character data and convert to something the parser knows
-            let mathml_str = HTML_ENTITIES.replace_all(&mathml_str, |cap: &Captures| match HTML_ENTITIES_MAPPING.get(&cap[1]) {
+            let mathml_str = HTML_ENTITIES.replace_all(mathml_str, |cap: &Captures| match HTML_ENTITIES_MAPPING.get(&cap[1]) {
                     None => {
                         error_message = format!("No entity named '{}'", &cap[0]);
                         cap[0].to_string()